SERVICE MANUAL COMMAND CV17-750 VERTICAL CRANKSHAFT
Contents Section 1. Safety and General Information ............................................................................ Section 2. Tools & Aids .......................................................................................................... Section 3. Troubleshooting ..................................................................................................... Section 4. Air Cleaner and Air Intake System ........................................................................
Section 1 Safety and General Information 1 Section 1 Safety and General Information Safety Precautions To ensure safe operation please read the following statements and understand their meaning. Also refer to your equipment manufacturer's manual for other important safety information. This manual contains safety precautions which are explained below. Please read carefully.
Section 1 Safety and General Information WARNING WARNING Explosive Fuel can cause fires and severe burns. Carbon Monoxide can cause severe nausea, fainting or death. Do not fill the fuel tank while the engine is hot or running. Avoid inhaling exhaust fumes, and never run the engine in a closed building or confined area. Explosive Fuel! Gasoline is extremely flammable and its vapors can explode if ignited.
Section 1 Safety and General Information Engine Identification Numbers When ordering parts, or in any communication involving an engine, always give the Model, Specification and Serial Numbers, including letter suffixes if there are any. 1 Identification Decal The engine identification numbers appear on a decal, or decals, affixed to the engine shrouding. See Figure 1-1. An explanation of these numbers is shown in Figure 1-2. Figure 1-1. Engine Identification Decal Location. A. Model No.
Section 1 Safety and General Information Oil Recommendations Using the proper type and weight of oil in the crankcase is extremely important. So is checking oil daily and changing oil regularly. Failure to use the correct oil, or using dirty oil, causes premature engine wear and failure. Oil Type Use high-quality detergent oil of API (American Petroleum Institute) Service Class SG, SH, SJ or higher. Select the viscosity based on the air temperature at the time of operation as shown in the following table.
Section 1 Safety and General Information Periodic Maintenance Instructions 1 WARNING: Accidental Starts! Disabling engine. Accidental starting can cause severe injury or death. Before working on the engine or equipment, disable the engine as follows: 1) Disconnect the spark plug lead(s). 2) Disconnect negative (-) battery cable from battery. Maintenance Schedule These required maintenance procedures should be performed at the frequency stated in the table.
Section 1 Safety and General Information Dimensions in millimeters. Inch equivalents shown in [ ]. Figure 1-4. Typical Engine Dimensions CV Series with Standard Flat Air Cleaner. 1.
Section 1 Safety and General Information Dimensions in millimeters. Inch equivalents shown in [ ]. Figure 1-5. Typical Engine Dimensions CV Series with Commercial Mower Air Cleaner. 1.
Section 1 Safety and General Information Dimensions in millimeters. Inch equivalents shown in [ ]. Figure 1-6. Typical Engine Dimensions CV EFI Series with Heavy-Duty Air Cleaner. 1.
Section 1 Safety and General Information General Specifications1 Power (@3600 RPM, exceeds Society of Automotive Engineers-Small Engine Test Code J1940.) CV17 ........................................................................................................................................... 12.7 kW (17 HP) CV18 ........................................................................................................................................... 13.4 kW (18 HP) CV20 ...............................
Section 1 Safety and General Information General Specifications1 cont. Oil Capacity (w/filter) - approximate, determined by oil filter and oil cooler used: ........................................................ 1.6-1.8 L (1.7-1.9 U.S. qt.) Angle of Operation - Maximum (At Full Oil Level) All Directions .................. 25° Blower Housing and Sheet Metal M5 Fasteners Torque ................................................................................................ 6.2 N·m (55 in. lb.
Section 1 Safety and General Information Crankcase Governor Cross Shaft Bore I.D. 6 mm Shaft New .............................................................................................................. 6.025/6.050 mm (0.2372/0.2382 in.) Max. Wear Limit ........................................................................................ 6.063 mm (0.2387 in.) 8 mm Shaft New .............................................................................................................. 8.025/8.
Section 1 Safety and General Information Cylinder Bore Cylinder Bore I.D. New - CV17 ............................................................................................. 73.006/73.031 mm (2.8742/2.8752 New - CV18,CV20,CV22 (624 cc) ......................................................... 77.000/77.025 mm (3.0315/3.0325 New - CV22/23 (674 cc) ......................................................................... 80.000/80.025 mm (3.1496/3.1506 New - CV25,CV26,CV730-750 ..........................
Section 1 Safety and General Information Ignition Spark Plug Type (Champion® or Equivalent) ............................................. RC12YC, XC12YC, or Platinum 3071 1 Spark Plug Gap ............................................................................................... 0.76 mm (0.030 in.) Spark Plug Torque .......................................................................................... 24.4-29.8 N·m (18-22 ft. lb.) Ignition Module Air Gap ...........................................
Section 1 Safety and General Information Piston, Piston Rings, and Piston Pin cont. Top and Middle Compression Ring End Gap New Bore - CV17 Top Ring ............................................................................................... 0.180/0.380 mm (0.0071/0.0150 in.) Middle Ring ......................................................................................... 0.180/0.440 mm (0.0071/0.0173 in.) New Bore - CV18,CV20,CV22 (624 cc) ................................................. 0.25/0.
Section 1 Safety and General Information Stator Mounting Screw Torque ................................................................................ 6.2 N·m (55 in. lb.) 1 Valve Cover Valve Cover Fastener Torque Gasket Style Cover .................................................................................. 3.4 N·m (30 in. lb.) Black O-Ring Style Cover w/Shoulder Screws ............................................................................ 5.6 N·m (50 in. lb.) w/Flange Screws and Spacers ....
Section 1 Safety and General Information General Torque Values Metric Fastener Torque Recommendations for Standard Applications Tightening Torque: N·m (in. lb.) + or - 10% Property Class 4.8 Size M4 M5 M6 M8 1.2 (11) 2.5 (22) 4.3 (38) 10.5 (93) 5.8 1.7 (15) 3.2 (28) 5.7 (50) 13.6 (120) 8.8 2.9 (26) 5.8 (51) 9.9 (88) 24.4 (216) Noncritical Fasteners Into Aluminum 10.9 4.1 (36) 8.1 (72) 14.0 (124) 33.9 (300) 12.9 5.0 (44) 9.7 (86) 16.5 (146) 40.7 (360) 2.0 (18) 4.0 (35) 6.8 (60) 17.
Section 1 Safety and General Information English Fastener Torque Recommendations for Standard Applications 1 Tightening Torque: N·m (in. lb.) + or - 20% Bolts, Screws, Nuts and Fasteners Assembled Into Cast Iron or Steel Grade 2 Size 8-32 10-24 10-32 1/4-20 1/4-28 5/16-18 5/16-24 3/8-16 3/8-24 2.3 (20) 3.6 (32) 3.6 (32) 7.9 (70) 9.6 (85) 17.0 (150) 18.7 (165) 29.4 (260) 33.9 (300) Grade 2 or 5 Fasteners Into Aluminum Grade 5 2.8 (25) 4.5 (40) 4.5 (40) 13.0 (115) 15.8 (140) 28.3 (250) 30.
Section 2 Tools & Aids Section 2 Tools & Aids 2 Certain quality tools are designed to help you perform specific disassembly, repair, and reassembly procedures. By using tools designed for the job, you can properly service engines easier, faster, and safer! In addition, you'll increase your service capabilities and customer satisfaction by decreasing engine downtime. Here is the list of tools and their source. Separate Tool Suppliers: Kohler Tools Contact your source of supply. SE Tools 415 Howard St.
Section 2 Tools & Aids Tools (cont.) Description Source/Part No. Flyw heel St r ap Wr ench To hold flywheel during removal. S E Tools KLR-82409 Hydr aulic Valve Lift er Tool To remove and install hydraulic lifters. Kohler 25 761 38-S Ignit ion Syst em Test er For testing output on all systems, except CD. For testing output on capacitive discharge (CD) ignition system. Kohler 25 455 01-S Kohler 24 455 02-S Offset Wr ench (K & M Ser ies) To remove and reinstall cylinder barrel retaining nuts.
Section 2 Tools & Aids Aids Description Source/Part No. Cam shaft Lubr icant (Valspar ZZ613) Kohler 25 357 14-S Dielect r ic Gr ease (GE/Novaguard G661) Kohler 25 357 11-S Dielect r ic Gr ease (Fel-Pro) Lubri-S el Elect r ic St ar t er Dr ive Lubr icant (Inertia Drive) Kohler 52 357 01-S Elect r ic St ar t er Dr ive Lubr icant (S olenoid S hift) Kohler 52 357 02-S RTV Silicone Sealant Loctite® 5900 Heavy Body in 4 oz aerosol dispenser.
Section 2 Tools & Aids Special Tools You Can Make Flywheel Holding Tool A flywheel holding tool can be made out of an old junk flywheel ring gear as shown in Figure 2-1, and used in place of a strap wrench. 1. Using an abrasive cut-off wheel, cut out a six tooth segment of the ring gear as shown. 2. Grind off any burrs or sharp edges. 3. Invert the segment and place it between the ignition bosses on the crankcase so that the tool teeth engage the flywheel ring gear teeth.
Section 3 Troubleshooting Section 3 Troubleshooting Troubleshooting Guide When troubles occur, be sure to check the simple causes which, at first, may seem too obvious to be considered. For example, a starting problem could be caused by an empty fuel tank. Some general common causes of engine troubles are listed below. Use these to locate the causing factors. Refer to the specific section(s) within this service manual for more detailed information. Engine Cranks But Will Not Start 1. Empty fuel tank. 2.
Section 3 Troubleshooting Engine Will Not Idle 1. Dirt or water in the fuel system. 2. Stale fuel and/or gum in carburetor. 3. Faulty spark plugs. 4. Fuel supply inadequate. 5. Idle fuel adjusting needle improperly set (some models). 6. Idle speed adjusting screw improperly set. 7. Low compression. 8. Restricted fuel tank cap vent. 9. Engine overheated-cooling system/air circulation problem. Engine Overheats 1. Air intake/grass screen, cooling fins, or cooling shrouds clogged. 2. Excessive engine load. 3.
Section 3 Troubleshooting • Check the condition of the oil. Drain the oil into a container - the oil should flow freely. Check for metal chips and other foreign particles. Sludge is a natural by-product of combustion; a small accumulation is normal. Excessive sludge formation could indicate overrich carburetion, weak ignition, overextended oil change intervals or wrong weight or type of oil was used, to name a few. NOTE: It is good practice to drain oil at a location away from the workbench.
Section 3 Troubleshooting No Crankcase Vacuum/Pressure in Crankcase Possible Cause Solution 1. Crankcase breather clogged or inoperative. 1. Disassemble breather, clean parts thoroughly, reassemble, and recheck pressure. 2. Seals and/or gaskets leaking. Loose or improperly torqued fasteners. 2. Replace all worn or damaged seals and gaskets. Make sure all fasteners are tightened securely. Use appropriate torque values and sequences when necessary. 3.
Section 3 Troubleshooting Leakdown Test Results Air escaping from crankcase breather ...................................................... Rings or cylinder worn. Air escaping from exhaust system ............................................................ Defective exhaust valve/improper seating. Air escaping from carburetor ..................................................................... Defective intake valve/improper seating. Gauge reading in "low" (green) zone ....................................
Section 4 Air Cleaner and Air Intake System Section 4 Air Cleaner and Air Intake System Air Cleaners General These engines are equipped with a replaceable, highdensity paper air cleaner element. Most are also equipped with an oiled-foam precleaner which surrounds the paper element. Three different types are used. The "standard" type air cleaner is shown in Figure 4-1. The "commercial mower" type is shown in Figure 4-2, and the "heavyduty" air cleaner is shown in Figure 4-9.
Section 4 Air Cleaner and Air Intake System Precleaner Paper Element Service (Standard and Commercial Mower Types) Every 100 hours of operation (more often under extremely dusty or dirty conditions), replace the paper element. See Figures 4-5 or 4-6, and follow these steps: 1. Unhook the latches or loosen the cover retaining knob and remove the cover. 2. Remove the wing nut, element cover, and air cleaner element. Element Figure 4-3. Precleaner on Standard Air Cleaner. Precleaner Element 3.
Section 4 Air Cleaner and Air Intake System Air Cleaner Base Spitback Cup Precleaner Spitback Cup Gasket Rubber Seal 4 Air Cleaner Cover Element Knob Seal Element Cover Nut Element Cover Knob Figure 4-5. Air Cleaner System Components - Standard. *Plenum air cleaner system does not use a precleaner. Element Cover Nut Wing Nut Element Cover Air Cleaner Cover (Plenum*) Element Cover Retaining Knob Rubber Seal Stud Air Cleaner Cover (Std.) Precleaner Air Cleaner Base Figure 4-6.
Section 4 Air Cleaner and Air Intake System Air Cleaner Components Whenever the air cleaner cover is removed, or the paper element or precleaner are serviced, check the following: Air Cleaner Element Cover and Seal - Make sure element cover is not bent or damaged. Make sure the rubber sleeve seal is in place on the stud to prevent dust or dirt entry through the stud hole. 4. Remove the base and gasket. Carefully feed the breather hose through the base. 5. Reverse procedure to reassemble components.
Section 4 Air Cleaner and Air Intake System Heavy-Duty Air Cleaner General The heavy-duty air cleaner consists of a cylindrical housing, typically mounted to a bracket, and connected with a formed rubber hose to an adapter on the carburetor or throttle body/intake manifold (EFI units). The air cleaner housing contains a paper element and inner element, designed for longer service intervals. The system is CARB/EPA certified and the components should not be altered or modified in any way.
Section 4 Air Cleaner and Air Intake System Air Intake/Cooling System To ensure proper cooling, make sure the grass screen, cooling fan fins, and other external surfaces of the engine are kept clean at all times. Every 100 hours of operation (more often under extremely dusty or dirty conditions), remove the blower housing and other cooling shrouds.* Clean the cooling fins and external surfaces as necessary. Make sure the cooling shrouds are reinstalled. *Cleanout kits, Kohler Part No.
Section 5 Fuel System and Governor Section 5 Fuel System and Governor Description The Command vertical twins use two different types of fuel systems; carbureted, or electronic fuel injection (EFI). This section covers the standard carbureted fuel systems. The EFI fuel systems are covered in subsection 5B. The governor systems used are covered at the end of this section. WARNING: Explosive Fuel! Gasoline is extremely flammable and its vapors can explode if ignited.
Section 5 Fuel System and Governor Fuel Filter Most engines are equipped with an in-line filter. Periodically inspect the filter and replace with a genuine Kohler filter every 200 operating hours. Fuel Line In compliance with CARB Tier III Emission Regulations, carbureted engines with a "Family" identification number beginning with "6" or greater (See Figure 5-1), must use Low Permeation SAE 30 R7 rated fuel line; certified to meet CARB requirements. Standard fuel line may not be used.
Section 5 Fuel System and Governor Fuel System Tests When the engine starts hard, or turns over but will not start, it is possible that the problem is in the fuel system. To find out if the fuel system is causing the problem, perform the following tests. Troubleshooting – Fuel System Related Causes Test Conclusion 1. Check the following: a. Make sure the fuel tank contains clean, fresh, proper fuel. b. Make sure the vent in fuel tank cap is open. c. Make sure the fuel valve is open. d.
Section 5 Fuel System and Governor Fuel Pump 3. Remove the pulse line that connects the pump to the crankcase. General These engines are equipped with a pulse type fuel pump. The pumping action is created by the oscillation of positive and negative pressures within the crankcase. This pressure is transmitted to the pulse pump through a rubber hose connected between the pump and crankcase.
Section 5 Fuel System and Governor Slow Circuit: (See Figure 5-3) At low speeds the engine operates only on the slow circuit. As a metered amount of air is drawn through the slow air bleed jet, fuel is drawn through the main jet and further metered through the slow jet. Air and fuel are mixed in the body of the slow jet and exit to the transfer port. From the transfer port this air fuel mixture is delivered to the idle progression chamber.
Section 5 Fuel System and Governor Main Circuit: (See Figure 5-4) At high speeds/loads the engine operates on the main circuit. As a metered amount of air is drawn through the main air bleed jet, fuel is drawn through the main jet. The air and fuel are mixed in the main nozzle and then enter the main body of airflow, where further mixing of the fuel and air takes place. This mixture is then delivered to the combustion chamber. The carburetor has a fixed main circuit; no adjustment is possible.
Section 5 Fuel System and Governor Troubleshooting – Carburetor Related Causes Condition Possible Cause/Probable Remedy 1. Engine starts hard, runs roughly 1. Low idle fuel mixture/speed improperly adjusted. Adjust the low or stalls at idle speed. idle speed screw, then adjust the low idle fuel needle. 2. Engine runs rich (indicated by 2a. Clogged air cleaner. Clean or replace. black, sooty exhaust smoke, b. Choke partially closed during operation.
Section 5 Fuel System and Governor High Altitude Operation When operating the engine at altitudes of 1500 m (5000 ft.) and above, the fuel mixture tends to get overrich. This can cause conditions such as black, sooty exhaust smoke, misfiring, loss of speed and power, poor fuel economy, and poor or slow governor response. To compensate for the effects of high altitude, special high altitude jet kits are available. The kits include a new main jet, slow jet (where applicable), necessary gaskets and O-Rings.
Section 5 Fuel System and Governor NOTE: The tip of the idle fuel adjusting needle is tapered to critical dimensions. Damage to the needle and the seat in the carburetor body will result if the needle is forced. Low Idle Fuel Adjustment (Some Models) 5. Low Idle Fuel Needle Setting: Place the throttle into the "idle" or "slow" position. Turn the low idle fuel adjusting needle in (slowly) until engine speed decreases and then back out approximately 3/4 to 1 turn to obtain the best low speed performance. 6.
Section 5 Fuel System and Governor 5. Slide the carburetor off the retaining studs. Remove the fuel bowl retaining screw or fuel shut-off solenoid and drain the fuel into a safe container. Remove the bowl from the carburetor body. Governed Idle Spring Tab 16.5 mm (0.65 in.) Figure 5-7. Governed Idle Spring Location. Hold Throttle Lever Against Screw Figure 5-8. Holding Throttle Lever Against Idle Stop Screw (One-Barrel Carburetor).
Section 5 Fuel System and Governor Disassembly Use the carburetor repair kit (and the float repair kit if float components are to be replaced). Refer to Figure 5-10 for parts identification. The Kohler part number and the Nikki lot number are stamped on the choke side flange on top of the carburetor body. Refer to the parts manual for the carburetor involved to ensure the correct repair kits and replacement parts are used. Disassemble carburetor as follows after removal from the engine. See Figure 5-10. 1.
Section 5 Fuel System and Governor 6 4 26 2 18 5 1 24 3 25 7 17 23 21 8 16 22 15 20 9 10 19 14 or 11 13 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26.
Section 5 Fuel System and Governor Always use new gaskets when servicing or reinstalling carburetors. Repair kits are available which include new gaskets and other components. Service/repair kits available for Nikki carburetors and affiliated components are: Carburetor Repair Kit Float Kit High Altitude Kit (1525-3048 m/5,000-10,000 ft.) High Altitude Kit (Over 3048 m/10,000 ft.) Solenoid Assembly Kit Reassembly Procedure Reassembly is essentially the reverse of the disassembly procedure.
Section 5 Fuel System and Governor 8. When the proper float height is obtained, carefully reinstall the fuel bowl, with the O-Ring(s) in place, onto the carburetor. Secure with the four original screws. Torque the screws to 2.5 ± 0.3 N·m (23 ± 2.6 in. lb.). Reattach the accelerator pump hose (if so equipped), and secure with the clip. See Figure 5-16. Figure 5-14. Installing Float Assembly. 6. Hold the carburetor body so the float assembly hangs vertically and rests lightly against the fuel inlet needle.
Section 5 Fuel System and Governor 2. Remove the float pin screw and lift out the old float, pin, and inlet needle. See Figure 5-18. Discard all of the parts. The seat for the inlet needle is not serviceable, and should not be removed. Figure 5-18. Removing Float and Inlet Needle. 3. Remove and discard the round plug from the bottom of the slow jet tower of the carburetor body. Use an appropriate size flat screwdriver, and carefully remove the slow and main jets from the carburetor.
Section 5 Fuel System and Governor 11. Install the float and inlet needle down into the seat and carburetor body. Insert the new pivot pin through the float hinge and secure with the new retaining screw. See Figure 5-24. Figure 5-21. Installing Slow Jet. Figure 5-24. Installing Float Assembly. 12. Hold the carburetor body so the float assembly hangs vertically and rests lightly against the fuel inlet needle.
Section 5 Fuel System and Governor 14. When the proper float height is obtained, carefully install the new O-Rings for the fuel bowl and the accelerator pump transfer passage (if so equipped). See Figure 5-26. Figure 5-28. Installing Idle Fuel Adjusting Screw and Spring. Figure 5-26. Installing Fuel Bowl O-Rings. 15. Install the fuel bowl onto the carburetor. Secure with the four original screws. Torque the screws to 2.5 ± 0.3 N·m (23 ± 2.6 in. lb.).
Section 5 Fuel System and Governor 2. Remove the three screws securing the cover to the accelerator pump housing. Remove the cover, spring, and diaphragm. See Figure 5-30. Figure 5-32. Check Valve and Retaining Ring Installed. Figure 5-30. Accelerator Pump Cover and Diaphragm Removed. 3. Remove the retaining ring over the rubber check valve, using a snap ring pliers. Remove the check valve from the fuel delivery chamber. See Figure 5-31. Figure 5-31. Removing Retaining Ring. 4.
Section 5 Fuel System and Governor 5. Use a screw extractor (easy out) and remove the original choke shaft bushing with the old choke lever from the carburetor housing. Save the bushing to use as a driver for installing the new bushing. Discard the old lever. 6. Clean the I.D. of both choke shaft bores as required. Figure 5-34. Installing Accelerator Pump Housing Screws and Hose. 7. Insert the new bushing through the new choke lever from the outside, and start the bushing in the outer shaft bore.
Section 5 Fuel System and Governor 9. Install the new return spring onto the new choke shaft, so the upper leg of the spring is between the two formed "stops" on the end of the choke shaft. See Figure 5-38. Note: Make sure it stays in this location during the following step. Figure 5-38. Choke Shaft and Spring Details. 10. Slide the choke shaft and spring, into the carburetor.
Section 5 Fuel System and Governor Adjustment NOTE: Carburetor adjustments should be made only after the engine has warmed up. The carburetor is designed to deliver the correct fuelto-air mixture to the engine under all operating conditions. The main fuel jet is calibrated at the factory and is not adjustable*. The idle fuel adjusting needle is also set at the factory and normally does not need adjustment. Depending on model and application, engines may also be equipped with a "Governed Idle System.
Section 5 Fuel System and Governor Adjust to Midpoint Lean Adjust to Midpoint Lean Governed Idle Spring Tab Rich Rich Left Side Right Side Figure 5-40. Optimum Low Idle Fuel Settings. Figure 5-41. Governed Idle Spring Location. Models with Governed Idle System An optional governed idle control system is supplied on some engines. The purpose of this system is to maintain a desired idle speed regardless of ambient conditions (temperature, parasitic load, etc.) that may change.
Section 5 Fuel System and Governor Fuel Bowl Bowl Drain Screw Figure 5-43. Fuel Bowl Removed From Carburetor. 3. Remove the float pin screw and lift out the old float, pin and inlet needle. See Figure 5-44. Discard all of the parts. The seat for the inlet needle is not serviceable, and should not be removed. Figure 5-45. Float and Inlet Needle Details. 6. Install the float and inlet needle down into the seat and carburetor body.
Section 5 Fuel System and Governor Fuel Bowl Bowl Drain Screw Figure 5-47. Checking Float Height. NOTE: Be sure to measure from the casting surface, not the rubber gasket, if still attached. 9. When the proper float height is obtained, carefully reinstall the fuel bowl, using new O-Rings onto the carburetor. Secure with the four original screws. Torque the screws to 2.5 ± 0.3 N·m (23 ± 2.6 in. lb.). See Figure 5-48. Figure 5-48. Installing Fuel Bowl. 10.
Section 5 Fuel System and Governor Slow (Idle Fuel) Jets Main Nozzles O-Ring Main Jets Figure 5-51. Main Jets and Nozzles Removed. 4. Remove the screw securing the flat washer and ground lead (if equipped), from the top of the carburetor; then carefully pull (lift) out the two slow jets. The slow jets may be size/side specific, mark or tag for proper reassembly. Note the small O-Ring on the bottom of each jet. See Figure 5-52 and 5-53.
Section 5 Fuel System and Governor Nozzle End with Two Shoulders (Out/Down) Main Jets Figure 5-54. Installing Main Nozzles and Main Jets. 9. Make sure the O-Ring near the bottom of each slow jet is new, or in good condition. Align and insert the two slow jets into the top of carburetor. See Figure 5-53. Figure 5-56. Float and Inlet Needle Details. 13. Install the float and inlet needle down into the seat and carburetor body.
Section 5 Fuel System and Governor 4. Note the position of the spring legs and the choke plate for correct reassembly later. See Figure 5-60. Remove the two screws attaching the choke plate to the choke shaft. Pull the shaft out of the carburetor body and discard the removed parts. Figure 5-58. Checking Float Height. NOTE: Be sure to measure from the casting surface, not the rubber gasket, if still attached. 16.
Section 5 Fuel System and Governor 8. Turn the old bushing upside down and use it as a driver to carefully press or tap the new bushing into the carburetor body until it bottoms. Check that the choke lever pivots freely without restriction or binding. See Figure 5-62. 11. Place a drop of Loctite® on the threads of each new screw. Position and install the new choke plate to the flat side of the choke shaft. Start the two screws.
Section 5 Fuel System and Governor 4 5 8 7 6 9 9 2 32 3 31 1 30 29 28 21 20 27 17 26 22 23 18 24 25 19 11 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32.
Section 5 Fuel System and Governor Governor Adjustments General The engine is equipped with a centrifugal flyweight mechanical governor. It is designed to hold the engine speed constant under changing load conditions. The governor gear/flyweight mechanism is mounted inside the crankcase on the oil pan, and is driven off the gear on the camshaft. The governor works as follows: General The governed speed setting is determined by the position of the throttle control.
Section 5 Fuel System and Governor Sensitivity Adjustment Governor sensitivity is adjusted by repositioning the governor spring in the holes of the governor lever. If speed surging occurs with a change in engine load, the governor is set too sensitive. If a big drop in speed occurs when normal load is applied, the governor should be set for greater sensitivity. See Figure 5-66 and adjust as follows: 1. To increase the sensitivity, move the spring closer to the governor lever pivot point. 2.
Section 5 Fuel System and Governor Choke Lever Choke Lever Detail Screw Spring Washer Spacer Washer Lock Nut Bushing Fastener Choke Lever (See Detail at Left) Screw and Nut Choke Cable Control Bracket Linkage Control Lever Fastener Lock Nut Throttle Cable Clamp Blower Housing Washer Spring Fuel Pump Clamp Clip Bushing Fuel Line Spring Linkage Bushing Throttle Shaft Bracket Lever Spring Washer Locker Nut Spacer Throttle Lever Deflector (If So Equipped) (Place Between Valley Baffle and Thro
Section 5 Fuel System and Governor Screw Washer Lock Nut Spring Washer Spacer Bushing Choke Linkage Hex Nut Screw Choke Cable Throttle Control Lever Clamp and Screw 5 Lock Nut Control Bracket Screw Washer Spring Throttle Cable Throttle Linkage Fuel Pump Bushing Linkage Spring Clamp Fuel Throttle Shaft Bushing Throttle Shaft Bracket Governor Lever Governor Spring Washer Spacer Lock Nut Throttle Lever Deflector (If So Equipped) Figure 5-69. Governor/Controls Assembly (CV750). 5.
Section 5B EFI Fuel System Section 5B Electronic Fuel Injection (EFI) Fuel System Contents Page(s) Description Initial Starting/Priming Procedure ......................................................................................................................... 5B.2 Fuel Recommendations ................................................................................................................................... 5B.2-5B.3 EFI Fuel System Components ..............................................
Section 5B EFI Fuel System Description WARNING 2. For plastic-cased ECU's below 24 584 28-S, the system can be primed by manually cycling the fuel pump. a. Turn the key switch to the "on/run" position. The fuel pump will run for about three seconds and stop. Turn the switch off and back on to restart the fuel pump. Repeat this procedure until the fuel pump has cycled five times, then start the engine. Explosive Fuel can cause fires and severe burns. Fuel system ALWAYS remains under HIGH PRESSURE.
Section 5B EFI Fuel System Gasoline/Alcohol blends Gasohol (up to 10% ethyl alcohol, 90% unleaded gasoline by volume) is approved as a fuel for Kohler EFI engines. Other gasoline/alcohol blends are not approved. Gasoline/Ether blends Methyl Tertiary Butyl Ether (MTBE) and unleaded gasoline blends (up to a maximum of 15% MTBE by volume) are approved as a fuel for Kohler EFI engines. Other gasoline/ether blends are not approved.
Section 5B EFI Fuel System During certain operating periods such as cold starts, warm up, acceleration, etc., an air/fuel ratio richer than 14.7:1 is required and the system operates in an "open loop" mode. In "open loop" operation the oxygen sensor output is not used, and the controlling adjustments are based on the primary sensor signals and programmed maps only. The system operates "open loop" whenever the three conditions for closed loop operation (above) are not being met.
Section 5B EFI Fuel System Two different ECU styles have been used in CV EFI production. Each has a plastic case, but they differ in having a 24 pin or 32 pin connector block, and are identified as MSE 1.0 or MSE 1.1 respectively. See Figures 5B-1 and 5B-2. Basic function and operating control remains the same between the two, however due to differences in the internal circuitry as well as the wiring harness, the ECU's are not interchangeable.
Section 5B EFI Fuel System General The engine speed sensor is essential to engine operation; constantly monitoring the rotational speed (RPM) of the crankshaft. A ferromagnetic 60-tooth ring gear with two consecutive teeth missing is mounted on the flywheel. The inductive speed sensor is mounted 1.5 ± 0.25 mm (0.059 ± 0.010 in.) away from the ring gear. During rotation, an AC voltage pulse is created within the sensor for each passing tooth.
Section 5B EFI Fuel System General The throttle position sensor (TPS) is used to indicate throttle plate angle to the ECU. Since the throttle (by way of the governor) reacts to engine load, the angle of the throttle plate is directly related to the load on the engine. 3. a. Use an ohmmeter and connect the ohmmeter leads as follows to test: (See chart on page 5B.26 or 5B.29.). "24 Pin" (MSE 1.
Section 5B EFI Fuel System "24 Pin" (MSE 1.0) Plastic-Cased ECU: Pin circuits #8 and #4. "32 Pin" (MSE 1.1) Plastic-Cased ECU: Pin circuits #8 and #4. 7. Locate the service connector plug in the wiring harness. Connect a jumper wire from the TPS initialization pin #24 (violet wire) to the battery voltage pin (red wire), or use the jumper connector plug with the blue jumper wire. See Figure 5B-7. a. Repair or replace as required. b. Turn the idle speed screw back in to its original setting. c.
Section 5B EFI Fuel System 11. Reconnect the battery cable and all external loads. Remove the rubber band from the throttle lever. Readjust the idle speed to the equipment manufacturer's specified setting and recheck the high-speed, no-load RPM setting. Observe the overall performance. TPS Initialization Procedure For "32 Pin" (MSE 1.1) Plastic-Cased ECU Only ("Auto-Learn" Initialization) 1.
Section 5B EFI Fuel System General The engine (oil) temperature sensor (Figure 5B-8) is used by the system to help determine fuel requirements for starting (a cold engine needs more fuel than one at or near operating temperature). Mounted in the oil filter adapter housing, it has a temperature-sensitive resistor that extends into the oil flow. The resistance changes with oil temperature, altering the voltage sent to the ECU.
Section 5B EFI Fuel System The oxygen sensor can function only after being heated by exhaust temperatures to a minimum of 375°C (709°F). A cold oxygen sensor will require approximately 1-2 minutes at moderate engine load to warm sufficiently to generate a voltage signal. Proper grounding is also critical. The oxygen sensor grounds through the metal shell, so a good, solid, unbroken ground path back through the exhaust system components, engine, and wiring harness is required.
Section 5B EFI Fuel System Ω, the b. If the resistance is less than 1.0 MΩ sensor is bad, replace it. 5. With the oxygen sensor disconnected and engine not running, disconnect the main harness connector from the ECU and set the meter to the Rx1 scale. Check the circuit continuity as follows: "24 Pin" (MSE 1.0) Plastic-Cased ECU: Check for continuity from pin #15 of the ECU connector (see page 5B.26) to the shell of the oxygen sensor, and from pin #11 to the sensor connector terminal of the main harness.
Section 5B EFI Fuel System 2. Connect the black lead of VOA meter to a chassis ground location. Connect the red lead to the #86 terminal in relay connector (see Figure 5B-12). Set meter to test resistance (Rx1). Turn ignition switch from "off" to "on." Meter should indicate continuity (ground circuit is completed) for 1 to 3 seconds. Turn key switch back off. a. Clean the connection and check wiring if circuit was not completed.
Section 5B EFI Fuel System 1 2 3 5 4 6 7 Figure 5B-15. Style 2 Fuel Injector. General The fuel injectors mount into the throttle body/intake manifold, and the fuel rail attaches to them at the top end. Replaceable O-Rings on both ends of the injector prevent external fuel leakage and also insulate it from heat and vibration. A special clip connects each injector to the fuel rail and holds it in place. The O-Rings should be replaced anytime the injector is removed.
Section 5B EFI Fuel System Listen Here Figure 5B-17. Checking Injectors. 3. Disconnect the electrical connector from an injector and listen for a change in idle performance (only running on one cylinder) or a change in injector noise or vibration. If an injector is not operating, it can indicate either a bad injector, or a wiring/electrical connection problem. Check as follows: NOTE: Do not apply voltage to the fuel injector(s). Excessive voltage will burn out the injector(s).
Section 5B EFI Fuel System 10. Remove the manifold mounting bolts and separate the throttle body/manifold from the engine leaving the TPS, fuel rail, air baffle, injectors and line connections intact. Discard the old gaskets. Check For Leaks Figure 5B-19. Injector Inspection Points. 1. Engine must be cool. Depressurize fuel system through test valve in fuel rail. 2. Disconnect spark plug leads from spark plugs. 3.
Section 5B EFI Fuel System Ignition System General A high-voltage, solid-state, battery ignition system is used with the EFI system. The ECU controls the ignition output and timing through transistorized control of the primary current delivered to the coils. Based on input from the speed sensor, the ECU determines the correct firing point for the speed at which the engine is running. At the proper instant, it releases the flow of primary current to the coil.
Section 5B EFI Fuel System EFI engines are equipped with Champion RC12YC (Kohler Part No. 12 132 02-S) resistor spark plugs. Equivalent alternate brand plugs can also be used, but must be resistor plugs or permanent damage to the ECU will occur, in addition to affecting operation. Proper spark plug gap is 0.76 mm (0.030 in.). The condition of the wiring, connectors, and terminal connections is essential to system function and performance.
Section 5B EFI Fuel System pump preventing the continued delivery of fuel. In this situation, the MIL will go on, but it will go back off after 4 cranking revolutions if system function is OK. Once the engine is running, the fuel pump remains on. Service The fuel pumps are non-serviceable and must be replaced if determined to be faulty.
Section 5B EFI Fuel System General The fuel pressure regulator assembly maintains the required operating system pressure of 39 psi ± 3. A rubber-fiber diaphragm (see Figure 5B-26) divides the regulator into two separate sections; the fuel chamber and the pressure regulating chamber. The pressure regulating spring presses against the valve holder (part of the diaphragm), pressing the valve against the valve seat.
Section 5B EFI Fuel System 6. Install the new regulator by carefully pushing and rotating it slightly into the base or housing. Fuel Rail a. External Regulators with Square Base Housing Only; Install a new O-Ring between the regulator and the mounting bracket. Set the mounting bracket into position. Fuel Rail b. Secure the regulator in the base with the original retaining ring or screws. Be careful not to dent or damage the body of the regulator as operating performance can be affected. 7.
Section 5B EFI Fuel System General Special low permeation high-pressure fuel line with an SAE 30 R9 rating is required for safe and reliable operation, due to the higher operating pressure of the EFI system. If hose replacement is necessary, order Fuel Line Service Kit Part No. 25 111 37-S (containing 60" of high-pressure hose and 10 Oetiker clamps), or use only the type of hose specified. Special Oetiker clamps (Kohler Part No.
Section 5B EFI Fuel System Idle Speed Screw Throttle Linkage Linkage Bushing Damper Spring Figure 5B-34. Throttle Linkage/Governor Lever Connection. Figure 5B-33. Idle Speed Screw Details. Initial Governor Adjustment 2. Check if the engine has a high-speed throttle stop screw installed in the manifold casting boss. See Figure 5B-35. 5B The initial governor adjustment is especially critical on EFI engines because of the accuracy and sensitivity of the electronic control system.
Section 5B EFI Fuel System B. Setting the Initial Adjustment 1. Check the split where the clamping screw goes through the governor lever. See Figure 5B-38. There should be a gap of at least 1/32". If the tips are touching and there is no gap present, the lever should be replaced. If not already installed, position the governor lever on the cross shaft, but leave the clamping screw loose. Figure 5B-36. Inserting Feeler Gauge (Engines Without Stop Screw). b.
Section 5B EFI Fuel System 4. Verify that the governor has been set correctly. With the linkage still retained in the "Full Throttle" position (Step 2), unsnap the bushing clip, separate the linkage from the bushing, and remove the bushing from the lever. Follow Steps 3 and 4 in ''Checking the Initial Adjustment''. 5. Reconnect the dampening spring into its governor lever hole from the bottom. Reinstall the bushing and reattach the throttle linkage. See Figure 5B-34.
Section 5B EFI Fuel System Electrical System The EFI system is a 12 VDC negative ground system, designed to operate down to a minimum of 7.0 volts. If system voltage drops below this level, the operation of voltage sensitive components such as the ECU, fuel pump, and injectors will be intermittent or disrupted, causing erratic operation or hard starting. A fully charged, 12 volt battery with a minimum of 350 cold cranking amps is important in maintaining steady and reliable system operation.
Section 5B EFI Fuel System "32 Pin" (MSE 1.
Section 5B EFI Fuel System Fuel System WARNING: Fuel System Under Pressure! The fuel system operates under high pressure. System pressure must be relieved through the test valve in the fuel rail prior to servicing or removal of any fuel system components. Do not smoke or work near heaters or other fire hazards. Have a fire extinguisher handy and work only in a well-ventilated area. The function of the fuel system is to provide sufficient delivery of fuel at the system operating pressure of 39 psi ± 3.
Section 5B EFI Fuel System Example of Diagnostic Display 1. Diagnostic display initiated through ignition key sequencing. 2. Long Pause Short Pause 3. Code 32 3 4. 2 Long Pause 5. Code 61 6 1 6. Long Pause 7. Light remains on at end of transmission Figure 5B-40. 5B After the problem has been corrected, the fault codes may be cleared as follows. 1. Disconnect the negative (-) battery cable or the main harness connector for one minute. 2. Reconnect the cable and tighten securely.
Section 5B EFI Fuel System Diagnostic Code Summary cont. Blink C ode OBD2 P-Code Applicable to: "32 Pin" Connection or Failure Description (MSE 1.1) ECU/System Only "24 Pin" (MSE 1.0) Plastic-Cased ECU/System "32 Pin" (MSE 1.
Section 5B EFI Fuel System Code: Source: Explanation: 21 Engine Speed Sensor ECU receiving inconsistent tooth count signals from speed sensor. Expected Engine Response: Possible misfire as ECU attempts to resynchronize during which time fuel and spark calculations are not made. Possible Causes: 1. Engine Speed Sensor Related a. Sensor connector or wiring. b. Sensor loose or incorrect air gap. c. Flywheel key sheared. 2. Speed Sensor Ring Gear Related a. Damaged teeth. b.
Section 5B EFI Fuel System If the engine is still running rich (laboring, short on power) or lean popping or misfiring), the fuel mixture is suspect, probably incorrect TPS initialization or low fuel pressure. Code: Source: Explanation: 23 ECU ECU is unable to recognize or process signals from its memory. Expected Engine Response: Engine will not run. Possible Causes: 1. ECU (internal memory problem). a. Diagnosable only through the elimination of all other system/component faults.
Section 5B EFI Fuel System Code: Source: Explanation: 33 Oxygen Sensor/Fuel System "System too Rich" Temporary fuel adaptation control is at the upper limit. Expected Engine Response: Erratic performance. Will run rich (smoke). Possible Causes: 1. Fuel Supply Related (nothing lean – only rich) a. Restricted return line causing excessive fuel pressure. b. Fuel inlet screen plugged (in-tank fuel pump only). c. Incorrect fuel pressure at fuel rail. 2. Oxygen Sensor Related a.
Section 5B EFI Fuel System Code: 42 Source: Engine (Oil) Temperature Sensor Explanation: Not sending proper signal to ECU. Expected Engine Response: Engine will be hard to start because ECU can't determine correct fuel mixture. Possible Causes: 1. Temperature Sensor Related a. Sensor wiring or connection. 2. Engine Wiring Harness Related "24 Pin" (MSE 1.0) Plastic-Cased ECU: a. Pin circuits 4, 6 and/or 4A damaged (wires, connectors) or routed near noisy signal (coils, alternator, etc.). b.
Section 5B EFI Fuel System 3. Fuel Pump Relay Related a. Bad fuel pump relay. Primary side functional but pin 30 to pin 87 remains open. Primary side pin 85 to pin 86 is either open, or shorted during engine operation. Note: after key-off then key-on, code 56 would be set also. 4. ECU Related a. Circuit controlling injector #1 damaged. b. Circuit controlling fuel pump relay damaged. Code: 52 "32 Pin" (MSE 1.1) PlasticCased ECU only.
Section 5B EFI Fuel System Code: Source: Explanation: 5B.38 61 Denotes the end of fault codes. If signaled first, no other fault codes are present. Troubleshooting Flow Chart The following flow chart provides an alternative method of troubleshooting the EFI system. The chart will enable you to review the entire system in about 10-15 minutes.
Section 5B EFI Fuel System 5B *Operate for an appropriate period of time based upon original fault codes. Figure 5B-41. 5B.
Section 5B EFI Fuel System Flow Chart Diagnostic Aids Diagnostic Aid #1 "SYSTEM POWER" (MIL does not illuminate when key is turned "on") Possible causes: 1. Battery 2. Main system fuse 3. MIL light bulb burned out 4. MIL electrical circuit problem "24 Pin" (MSE 1.0) Plastic-Cased ECU: Pin circuits 19 and 84. "32 Pin" (MSE 1.1) Plastic-Cased ECU: Pin circuits 29 and 84. 5. Ignition switch 6. Permanent ECU power circuit problem "24 Pin" (MSE 1.0) Plastic-Cased ECU: Pin circuit 1. "32 Pin" (MSE 1.
Section 5B EFI Fuel System Diagnostic Aid #5 "FUEL PUMP" (fuel pump not turning on) Diagnostic Aid #8 "FUEL SYSTEM-ELECTRICAL" (no fuel delivery) Possible causes: 1. Fuel pump fuse 2. Fuel pump circuit problem "24 Pin" (MSE 1.0) Plastic-Cased ECU: Circuits 30, 87, and relay. "32 Pin" (MSE 1.1) Plastic-Cased ECU: Circuits 30, 87, and relay. 3. Fuel pump Possible causes: 1. No fuel 2. Air in fuel rail 3. Fuel valve shut off 4. Fuel filter/line plugged 5. Injector circuit(s) "24 Pin" (MSE 1.
Section 6 Lubrication System Section 6 Lubrication System General This engine uses a full pressure lubrication system, delivering oil under pressure to the crankshaft, camshaft, and connecting rod bearing surfaces. In addition to lubricating the bearing surfaces, the lubrication system supplies oil to the hydraulic valve lifters. A high-efficiency gerotor pump is located in the oil pan. The oil pump maintains high oil flow and oil pressure, even at low speeds and high operating temperatures.
Section 6 Lubrication System Checking Oil Level The importance of checking and maintaining the proper oil level in the crankcase cannot be overemphasized. Check oil BEFORE EACH USE as follows: 1. Make sure the engine is stopped, level, and is cool so the oil has had time to drain into the sump. 2. Clean the area around the oil fill cap/dipstick before removing it. This will help to keep dirt, grass clippings, etc., out of the engine. 3. Unthread and remove the oil fill cap/dipstick; wipe oil off.
Section 6 Lubrication System Change the oil as follows: 1. A drain plug is located on either side of the oil sump; one is near the starter, the other is near the oil filter. See Figures 6-4 and 6-5. Clean the area around the most accessible oil drain plug and the oil fill cap/dipstick. 2. Remove the selected drain plug and the oil fill cap/dipstick. 3. Allow the oil to drain and then reinstall the drain plug. Torque to 13.6 N·m (10 ft. lb.). 4.
Section 6 Lubrication System To service the blower housing mounted oil cooler, clean the outside of the fins with a brush (see Figure 6-7). Remove the two screws holding the cooler unit to the blower housing. Tilt the cooler downward as shown in Figure 6-8. Clean the inside of the cooler with a brush or with compressed air. After cleaning, reinstall the oil cooler to the blower housing with the two mounting screws. Oil Sentry™ Figure 6-9. Oil Sentry™ Location.
Section 7 Retractable Starter Section 7 Retractable Starter WARNING: Spring Under Tension! Retractable starters contain a powerful, recoil spring that is under tension. Always wear safety goggles when servicing retractable starters and carefully follow instructions in this section for relieving spring tension. Hex Flange Screws Starter Housing Handle with Rope Retainer 2. Pull the starter handle out until the pawls engage in the drive cup. Hold the handle in this position and tighten the screws securely.
Section 7 Retractable Starter 6. Tie a single knot in one end of the new rope. Pawls (Dogs) Replacement 7. Rotate the pulley counterclockwise (when viewed from pawl side of pulley) until the spring is tight (approximately 6 full turns of pulley). To replace the pawls, follow disassembly steps 1-4 and reassembly steps 3-8 on the following pages. A pawl repair kit is available which includes the following components: 8.
Section 7 Retractable Starter Center Screw and Washer Pawl Retainer Housing Pulley Figure 7-4. Center Screw, Washer and Pawl Retainer. Figure 7-6. Removing Pulley from Housing. 8. Note the position of the spring and keeper assembly in the pulley. See Figure 7-7. Brake Spring and Brake Washer Pawl Spring Remove the spring and keeper assembly from the pulley as a package. WARNING: Spring Under Tension! Do not remove the spring from the keeper.
Section 7 Retractable Starter 3. Do not attempt to rewind a spring that has come out of the keeper. Order and install a new spring and keeper assembly. Pawl 4. Clean all old grease and dirt from the starter components. Generously lubricate the spring and center shaft with any commercially available bearing grease. Reassembly 1. Make sure the spring is well lubricated with grease. Place the spring and keeper assembly into the pulley (with spring toward pulley). See Figure 7-7. 2.
Section 8 Electrical System and Components Section 8 Electrical System and Components This section covers the operation, service, and repair of the electrical system components. Systems and components covered in this section are: • Spark Plugs • Battery and Charging System • Electronic CD Ignition System (including SMARTSPARK™ on applicable models) • Electric Starter NOTE: Do not clean spark plugs in a machine using abrasive grit.
Section 8 Electrical System and Components Normal: A plug taken from an engine operating under normal conditions will have light tan or gray colored deposits. If the center electrode is not worn, a plug in this condition could be set to the proper gap and reused. Carbon Fouled: Soft, sooty, black deposits indicate incomplete combustion caused by a restricted air cleaner, over-rich fuel mixture, weak ignition, or poor compression.
Section 8 Electrical System and Components Battery General A 12-volt battery with 400 cold cranking amps is generally recommended for starting in all conditions. A smaller capacity battery is often sufficient if an application is started only in warmer temperatures. Refer to the following table for minimum cold cranking amp (cca) capacities, based on anticipated ambient temperatures. The actual cold cranking requirement depends on engine size, application, and starting temperatures.
Section 8 Electrical System and Components Electronic CD Ignition Systems Red Ignition Module Input Red Starter and Carburetor Solenoid Input Red Green Carburetor Solenoid Oil Pressure Safety Spark Advance Module (Optional) White Red Oil Pressure B+ and Spark Safety Input Carburetor Plugs Solenoid Input B+ Violet RectifierRegulator Ignition Modules White Figure 8-3. Electronic CD Ignition System (For Customer Connected Tractor Applications).
Section 8 Electrical System and Components Kill Switch or ''Off'' Position of Key Switch Ignition Modules Spark Plug Magnet 0.28/0.33 mm (0.011/0.013 in.) Air Gap Flywheel Figure 8-4. Capacitive Discharge (Fixed Timing) Ignition System. The timing of the spark is controlled by the location of the flywheel magnet group as referenced to engine top dead center. D1 8 C1 T1 SCS Spark Plug L1 L2 P S Figure 8-5. Capacitive Discharge Ignition Module Schematic.
Section 8 Electrical System and Components B. Capacitive Discharge with Electronic Spark Advance (SMART-SPARK™) SMART-SPARK™ equipped engines utilize an electronic capacitive discharge ignition system with electronic spark advance. A typical application (Figure 8-6) consists of the following components: A magnet assembly which is permanently affixed to the flywheel. • Two electronic capacitive discharge ignition modules which mount on the engine crankcase (Figure 8-6).
Section 8 Electrical System and Components Operation: The ignition module for this system operates in the same fashion as the fixed timing module, except the trigger circuit for the semiconductor (L2, Figure 8-5) is replaced by the spark advance module (Figure 8-7). The pulse generated by the input coil of the ignition module (L1, Figure 8-5) is fed to the input of the conditioning circuit. The conditioning circuit shapes this pulse, putting it in a useable form for the additional circuits.
Section 8 Electrical System and Components a. If one side is not firing, check all wiring, connections, and terminations on that side. If wiring is okay, replace ignition module and retest for spark. b. If the tester shows spark, but the engine misses or won't run on that cylinder, try a new spark plug. c. If neither side is firing, recheck position of ignition switch and check for shorted kill lead.
Section 8 Electrical System and Components Test 3. Check for timing advance. Test 4. Test the ignition modules and connections. 1. Remove the blower housing from the engine. Inspect the wiring for any damage, cuts, bad crimps, loose terminals or broken wires. 2. Disconnect the leads from the ignition module(s) and clean all of the terminals (male and female) with aerosol electrical contact cleaner to remove any old dielectric compound, dark residue, dirt, or contamination.
Section 8 Electrical System and Components Ignition Module Resistance Table 24 584 03 or 24 584 11 24 584 15-S or 24 584 36-S (1 11/16 in. High) (2 1/16 in. High) 2 1 4 2 1 5) Loosen the mounting screws, allow the magnet to pull the module down against the feeler gauge, and retighten the mounting screws. 3 Test 24 584 03 24 584 15-S 24 584 36-S (Use Digital 24 584 11 (2 1/16 in. H) (2 1/16 in. H) Ohmmeter) (1 11/16 in. H) From No.
Section 8 Electrical System and Components a. If correct voltage is not measured, connect black voltmeter lead directly to the negative (-) post of the battery and test voltage again in both key positions. If correct voltage is now indicated, check the ground circuit connections. If the ground screw/bolt or any other fasteners in the ground circuit are black (oxide-coated), replace them with zinc plated (silver colored) fasteners. b.
Section 8 Electrical System and Components Figure 8-12. 2. Check the SAM part number stamped on the side of the housing. Verify that you have an analog SAM (ASAM) Part No. 24 584 10 or lower, not a digital SAM (DSAM) Part No. 24 584 18 and higher. Follow sub-step a for testing an ASAM with this tester. Digital SAM (DSAM) modules require Tester 25 761 40-S for proper testing. a. Depress the tester button and hold it down.
Section 8 Electrical System and Components b. If it is a DSAM (all except 24 584 09 or 24 584 10), connect the tester as follows: To Test – Using 25 761 40-S Tester DSAM/ASAM Test Procedure • Yellow tester lead to the long yellow module lead. • Brown tester lead to the long brown module lead. • Red tester lead to the red module lead. • Black tester lead to the green or black module ground lead with the eyelet# terminal. • Pink tester lead to the short yellow or pink module lead.
Section 8 Electrical System and Components 4. If you get a "-" sign instead of the numerical sequence, and/or an "F" at the end of the test cycle, recheck all of the connections, check the condition of the tester battery** and repeat the test. If you get the "-"or "F" sign again in the retest replace the SAM. *IMPORTANT! Allow 15-20 seconds for the tester to clear and reset itself between tests or if the test is interrupted before completion of the test cycle.
Section 8 Electrical System and Components 15/20/25 Amp Regulated Charging System 8 Figure 8-17. Wiring Diagram - 15/20/25 Amp Regulated Battery Charging System with Fixed Timing. 8.
Section 8 Electrical System and Components Figure 8-18. Wiring Diagram - 15/20/25 Amp Regulated Battery Charging System with Variable Ignition Timing SMART-SPARK™. Figure 8-19. 15 Amp Stator and Rectifier-Regulator. 8.16 Figure 8-20. 20 Amp Stator and Rectifier-Regulator.
Section 8 Electrical System and Components 1st Style 25 Amp Stator 2nd Style Figure 8-21. 25 Amp Stator and Rectifier-Regulators. 3 Amp Unregulated Charging System Ground-To-Kill Lead (White) A Light 8 R Ignition Modules (Blue) S B (Red) GND Spark Plug Spark Plug Keyswitch (Black) Optional Fuse Optional Oil SentryTM Switch (Indicator Light) Diode (Yellow) Optional Ammeter 3 Amp/70 Watt Flywheel Stator Lights Optional Oil SentryTM Switch (Shutdown) 12 V.
Section 8 Electrical System and Components 3 Amp Charging Stator Lighting Lead (Yellow) Diode Charging Lead (Black) Lighting Stator Figure 8-23. 3 Amp/70 Watt Stator. Stator The stator is mounted on the crankcase behind the flywheel. Follow the procedures in Section 9 "Disassembly" and Section 11 - "Reassembly" if stator replacement is necessary. Rectifier-Regulator The rectifier-regulator is mounted on the blower housing. See Figure 8-24.
Section 8 Electrical System and Components 3. Plug the tester into the proper AC outlet/power supply for tester being used. Turn on the power switch. See Figure 8-26. The ''POWER'' light should be illuminated and one of the four status lights may be on as well. This does not represent the condition of the part. 20/25 Amp Rectifier-Regulators 1. Connect the single lead adapter in between the B+ (center) terminal of the rectifier-regulator being tested and the squared single end of the tandem adapter lead.
Section 8 Electrical System and Components 6. Press the ''TEST'' button until a ''click'' is heard and then release. See Figure 8-27. Momentarily one of the four status lights will illuminate indicating the partial condition of the part. a. If the ''OK'' (green) light comes on, disconnect the tester black lead attached to one AC terminal and reconnect it to the other AC terminal. Repeat the test. If the ''OK'' (green) light comes on again, the part is good and may be used. b.
Section 8 Electrical System and Components 4. Press the ''TEST'' button until a "click" is heard and then release. See Figure 8-27. Momentarily either the ''HIGH'', ''LOW'', or ''SHORT'' light will flash. a. If the "HIGH" light flashes on/off, the part is good and may be used. b. If any other light is displayed* the rectifier is faulty and should not be used. *NOTE: A flashing "LOW" light can also occur as a result of an inadequate ground lead connection.
Section 8 Electrical System and Components Troubleshooting Guide 15/20/25 Amp Battery Charging Systems When problems occur in keeping the battery charged or the battery charges at too high a rate, the problem can usually be found somewhere in the charging system or with the battery. NOTE: Always zero ohmmeter on each scale before testing to ensure accurate readings. Voltage tests should be made with the engine running at 3600 RPM - no load. The battery must be good and fully charged. Problem Test 1.
Section 8 Electrical System and Components Troubleshooting Guide 3 Amp Battery Charging System with 70 Watt Lighting Stator NOTE: Zero ohmmeters on each scale to ensure accurate readings. Voltage tests should be made with engine running at 3000 RPM - no load. Battery must be good and fully charged. Problem Test 1. With engine running at 3000 RPM, measure voltage across battery terminals using a DC voltmeter. Conclusion 1. If voltage is more than 12.5 volts, charging system is OK. If voltage is 12.
Section 8 Electrical System and Components Electric Starting Motors Some engines in this series use inertia drive starting motors while most use solenoid shift starters. The inertia drive types are covered first and the solenoid shift types following. Starting Motor Precautions NOTE: Do not crank the engine continuously for more than 10 seconds at a time. If the engine does not start, allow a 60-second cool-down period between starting attempts.
Section 8 Electrical System and Components Operation - Inertia Drive Starters When power is applied to the starter, the armature rotates. As the armature rotates, the drive pinion moves out on the drive shaft splines and into mesh with the flywheel ring gear. When the pinion reaches the end of the drive shaft, it rotates the flywheel and "cranks" the engine. 7. Install the drive pinion, dust cover spacer, antidrift spring, stop gear spacer, and stop nut. Torque the stop nut to 17.0-19.2 N·m (150-170 in.
Section 8 Electrical System and Components Style ''B'' Drive Service 1. The rubber dust cover has a molded lip on the inside that snaps into a groove in the dust cover spacer (see Figure 8-35). Turn the drive pinion clockwise until it reaches the fully extended position. While holding it in the extended position, grasp the tip of the dust cover with a pliers or vise grip and pull it free from the spacer.
Section 8 Electrical System and Components Retaining Ring Installation 1. Position the retaining ring in the groove in one of the inner halves. Assemble the other half over the top and slide on the outer collar. 2. Be certain the drive components are installed in correct sequence onto the armature shaft. 3. Slip the tool over the end of the armature shaft, so the retaining ring inside is resting on the end of the shaft. Hold the tool with one hand, exerting slight pressure toward the starter.
Section 8 Electrical System and Components NOTE: Use a brush holder tool to keep the brushes in the pockets. A brush holder tool can easily be made from thin sheet metal. See Figure 8-40. 2. Insert the armature into the starter frame. Make sure the magnets are closer to the drive shaft end of the armature. The magnets will hold the armature inside the frame. SelfTapping Screw 3. Install the drive end cap over the drive shaft. Make sure the match marks on the end cap and starter frame are aligned.
Section 8 Electrical System and Components Solenoid Shift Electric Starters The following subsection covers the solenoid shift electric starters. Much of the information in the proceeding subsection relates to this type starter also, so it is not repeated here. A Nippondenso or DelcoRemy solenoid shift starter may be used. The Nippondenso starter is covered first, and the DelcoRemy starter servicing follows. Figure 8-42. Style ''B'' Commutator End Cap with Brushes. 6.
Section 8 Electrical System and Components Starter Disassembly 1. Disconnect the lead wire from the solenoid. 2. Remove the hex nuts securing the solenoid, and remove the solenoid from the starter assembly. 3. Remove the two thru bolts. 4. Remove the commutator end cap. 5. Remove the insulator and the brush springs from the brush spring holder. Starter Service Every 500 hours of operation (or annually, whichever comes first), solenoid shift starters must be disassembled, cleaned and relubricated.
Section 8 Electrical System and Components Phillips Head Screws Torx Head Screws Figure 8-45. Removing Solenoid Screws. Figure 8-46. Solenoid Removed from Starter. 8 3. If the solenoid was mounted with Phillips head screws, separate the solenoid and plunger spring from the drive end cap. If the solenoid was mounted with external Torx head screws, the plunger is part of the solenoid, unhook the plunger pin from the drive lever. Remove the gasket from the recess in the housing.
Section 8 Electrical System and Components 7. Remove the drive lever pivot bushing and backing plate from the end cap. See Figure 8-51. Figure 8-48. Removing Thru Bolts. 5. Remove the commutator end plate assembly, containing the brush holder, brushes, springs, and locking caps. Remove the thrust washer from inside the commutator end. See Figure 8-49. Figure 8-51. 8. Take out the drive lever and pull the armature out of the drive end cap. See Figure 8-52. 9.
Section 8 Electrical System and Components Figure 8-53. Retaining Ring Detail. Figure 8-54. Removing Retaining Ring. 11. Remove the retainer from the armature shaft. Save the stop collar. 12. Remove the drive pinion assembly from the armature. NOTE: 13. Clean the parts as required. Do not reuse the old retainer. NOTE: Do not soak the armature or use solvent when cleaning. Wipe clean using a soft cloth, or use compressed air.
Section 8 Electrical System and Components Inspection Commutator O.D. Drive Pinion Check and inspect the following areas: a. The pinion teeth for abnormal wear or damage. b. The surface between the pinion and the clutch mechanism for nicks, or irregularities which could cause seal damage. c. Check the drive clutch by holding the clutch housing and rotating the pinion. The pinion should rotate in one direction only. Brushes and Springs Inspect both the springs and brushes for wear, fatigue, or damage.
Section 8 Electrical System and Components Brush Replacement Starter Service The brushes and springs are serviced as a set (4). Use Brush and Spring Kit, Kohler Part No. 25 221 01-S, if replacement is necessary. Clean the drive lever and armature shaft. Apply Kohler electric starter drive lubricant (see Section 2) (Versilube G322L or Mobil Temp SHC 32) to the lever and shaft. Clean and check the other starter parts for wear or damage as required. 1. Perform steps 1-5 in "Starter Disassembly." 2.
Section 8 Electrical System and Components 7. Install the backup washer, followed by the rubber grommet, into the matching recess of the drive end cap. The molded recesses in the grommet should be "out", matching and aligned with those in the end cap. See Figure 8-64. Figure 8-62. Installing Thrust Washer. 4. Apply a small amount of oil to the bearing in the drive end cap, and install the armature with the drive pinion. 5.
Section 8 Electrical System and Components Figure 8-66. Installing Thrust Washer. 10. Starter reassembly when replacing the Brushes/ Brush Holder Assembly: a. Hold the starter assembly vertically on the end housing, and carefully position the assembled brush holder assembly, with the supplied protective tube, against the end of the commutator/armature. The mounting screw holes in the metal clips must be "up/ out.
Section 8 Electrical System and Components Figure 8-70. Installing Brush Holder Assembly using Tool with Extension. 11. Install the end cap onto the armature and frame, aligning the thin raised rib in the end cap with the corresponding slot in the grommet of the positive (+) brush lead. 12. Install the two thru bolts, and the two brush holder mounting screws. Torque the thru bolts to 5.6-9.0 N·m (49-79 in. lb.). Torque the brush holder mounting screws to 2.5-3.3 N·m (22-29 in. lb.).
Section 8 Electrical System and Components Solenoid Test Procedure Solenoid Shift Style Starters Disconnect all leads from the solenoid including the positive brush lead attached to the lower stud terminal. Remove the mounting hardware and separate the solenoid from the starter for testing. Test 1. Solenoid Pull-In Coil/Plunger Actuation Test. Use a 12 volt power supply and two test leads. Connect one lead to the flat spade "S/start" terminal on the solenoid.
Section 8 Electrical System and Components Test 4. Solenoid Hold-In Coil/Contact Continuity Test. Use an ohmmeter set to the audible or Rx2K scale, and connect the two ohmmeter leads to the two large post terminals. Perform the preceding test (3) and check for continuity. See Figure 8-77. The meter should indicate continuity, if no continuity is indicated the solenoid should be replaced. Repeat test several times to confirm condition. Plunger Pushed "In" VOM Meter Leads 12 volt Test Leads Figure 8-77.
Section 9 Disassembly Section 9 Disassembly WARNING: Accidental Starts! Disabling engine. Accidental starting can cause severe injury or death. Before working on the engine or equipment, disable the engine as follows: 1) Disconnect the spark plug lead(s). 2) Disconnect negative (-) battery cable from battery. General Clean all parts thoroughly as the engine is disassembled. Only clean parts can be accurately inspected and gauged for wear or damage.
Section 9 Disassembly 3. Remove the mounting screw and detach the oil fill tube. See Figure 9-3. 4. Remove and discard the oil filter. See Figure 9-4. Remove Oil Cooler If equipped, the oil cooler can now be removed from the engine. Two different styles are used, see Figures 6-6 and 6-7 in Section 6. 1. Use a 5/16" allen wrench to remove the oil filter nipple. Figure 9-2. Removing Oil Fill Cap/Dipstick. 2. For the crankcase-mounted cooler: Separate the oil cooler from the oil pan.
Section 9 Disassembly Figure 9-6. Removing Standard Element and Precleaner. Figure 9-8. Removing Commercial Mower Element and Precleaner. 3. Remove the element cover, element and precleaner. See Figure 9-6. Hex Flange Nuts (2) Lower Mounting Screws (Some Models) 9 Figure 9-7. Removing Standard Air Cleaner Base. 4. Remove the two hex flange nuts securing the spitback cup, baffle or bracket, and air cleaner base. See Figure 9-7.
Section 9 Disassembly Heavy Duty Air Cleaner 1. Disconnect the breather hose from the fitting in adapter or elbow. Remove the hex flange nuts securing the adapter and any attached clips to the mounting studs. See Figure 9-10. 4. Remove the two upper screws securing the air cleaner mounting bracket to the blower housing and remove the air cleaner assembly. See Figures 9-12 and 9-13. Adapter Elbow Hex Nuts Upper Mounting Screws Breather Hose Figure 9-12. Removing Upper Mounting Screws. Figure 9-10.
Section 9 Disassembly Pulse Hose Figure 9-14. Removing Throttle Control Bracket. Figure 9-16. Disconnecting Pulse Line from Crankcase. Fuel Pump Inlet Hose Outlet Hose (To Carburetor) Pulse Hose Figure 9-15. Removing Control Panel. Mounting Screws Figure 9-17. Pulse Fuel Pump Details. 9 Remove Fuel Pump WARNING: Explosive Fuel! Gasoline may be present in the carburetor and fuel system. Gasoline is extremely flammable and its vapors can explode if ignited.
Section 9 Disassembly Control Bracket Figure 9-18. Removing Control Bracket. Air Cleaner Brackets (Some Models) Governor Lever Figure 9-20. Removing Governor Lever. Remove Carburetor WARNING: Explosive Fuel! Gasoline may be present in the carburetor and fuel system. Gasoline is extremely flammable, and its vapors can explode if ignited. Keep sparks and other sources of ignition away from the engine. 1. Disconnect the fuel shut-off solenoid lead if so equipped.
Section 9 Disassembly 3. Remove the carburetor, throttle linkage and governor lever as an assembly. 5. If necessary, the carburetor, throttle linkage and governor lever can be separated. Reattach the bushings to the linkage following separation to avoid losing them. Remove Electric Starter Motor 1. Disconnect the leads from the starter. 2. Remove the two hex flange screws. See Figure 9-25. Figure 9-22. Removing Carburetor and Linkage (Two-Barrel Model Pictured). Figure 9-25.
Section 9 Disassembly Remove Outer Baffles and Blower Housing 1. Disconnect the wire leads from the start switch on the blower housing (if so equipped). Disconnect the plug from the rectifier-regulator. Use the tip of the dipstick or a similar small flat tool to bend the locking tang, then remove the B+ terminal from the center position in the plug. See Figure 9-26. This will allow the blower housing to be removed without disturbing the wiring harness. Figure 9-27.
Section 9 Disassembly Remove Oil Sentry™ 1. Disconnect the lead from the Oil Sentry™ switch. 2. Remove the Oil Sentry™ switch from the breather cover. See Figure 9-33. Figure 9-30. Removing Flywheel Screen. 6. Remove the remaining hex flange screws securing the blower housing. Note the one silver plated screw used for the rectifier-regulator ground strap or lead. Remove the blower housing. See Figures 9-31 and 9-32. Figure 9-33. Removing Oil Sentry™ Switch.
Section 9 Disassembly Figure 9-35. Break Breather Cover Seal. 5. Remove the breather cover and gasket (if used). See Figure 9-36. Figure 9-37. Removing Valve Cover. Remove Ignition Modules 1. Disconnect the lead(s) from each ignition module. See Figure 9-38. SMART-SPARK™ Module Leads Figure 9-36. Removing Breather Cover Gasket. Remove Valve Covers Three valve cover designs have been used. The earliest type used a gasket and RTV sealant between the cover and sealing surface of the cylinder head.
Section 9 Disassembly Aluminum Intake Manifold Figure 9-39. Position of Ignition Modules. 3. Remove the mounting screws and ignition modules. Note the position of the ignition modules. Remove Intake Manifold 1. Remove the four hex flange screws securing the intake manifold to the cylinder heads. Note which screws hold the wiring clamps. 2. Remove the intake manifold and the intake manifold gaskets (aluminum intake manifolds) or O-Ring (plastic intake manifolds). See Figure 9-40.
Section 9 Disassembly Remove Cylinder Heads and Hydraulic Lifters NOTE: Cylinder heads are retained using either hex flange screws or hex flange nuts and washers on studs. Do not interchange or mix components, as the cylinder heads may have different machining, unique to each fastening method. 1. Remove the four hex flange screws or hex nuts and washers securing each cylinder head. See Figure 9-42. Discard the screws or nuts and washers once removed. Do not reuse.
Section 9 Disassembly Valve Keepers Cap Retainer Spring Figure 9-45. Removing Rocker Arm. Figure 9-47. Valve Components. 2. Compress the valve springs using a valve spring compressor. See Figure 9-46. Valve Seal Figure 9-48. Intake Valve Seal Location. Figure 9-46. Removing Valves with Valve Spring Compressor. 3. Once the valve spring is compressed, remove the following items.
Section 9 Disassembly Figure 9-49. Removing Plastic Grass Screen. 2. Remove the four hex flange screws or hex studs and washers. Remove the plastic fan from the flywheel. See Figure 9-50. Figure 9-51. Removing Flywheel Fastener Using Strap Wrench. 2. Remove the hex flange screw and washer. 3. Use a puller to remove the flywheel from the crankshaft. See Figure 9-52. NOTE: Always use a flywheel puller to remove the flywheel from the crankshaft.
Section 9 Disassembly 2. Locate the splitting tabs cast into the perimeter of the oil pan. Insert the drive end of a 1/2" breaker bar between the splitting tab and the crankcase and turn it to break the RTV seal. See Figure 9-55. Do not pry on the sealing surfaces as this can cause leaks. Governor Gear Assembly The governor gear assembly is located inside the oil pan. If service is required, refer to the service procedures under "Governor Gear Assembly" in Section 10. Figure 9-53.
Section 9 Disassembly Remove Connecting Rods with Pistons and Rings 1. Remove the two hex flange screws securing the closest connecting rod end cap. Remove the end cap. See Figure 9-60. Figure 9-57. Removing Governor Cross Shaft Hitch Pin (6 mm Shaft Design). Figure 9-60. Removing Connecting Rod End Cap. NOTE: If a carbon ridge is present at the top of either cylinder bore, use a ridge reamer tool to remove it before attempting to remove the piston. 2.
Section 9 Disassembly 3. Repeat the above procedure for the other connecting rod and piston assembly. Remove Crankshaft Remove Flywheel End Oil Seal 1. Remove the oil seal from the crankcase. See Figure 9-63. 1. Carefully pull the crankshaft from the crankcase. See Figure 9-62. Figure 9-63. Removing Oil Seal. Figure 9-62. Removing Crankshaft. 9 9.
Section 10 Inspection and Reconditioning Section 10 Inspection and Reconditioning This section covers the operation, inspection, and repair/reconditioning of major internal engine components. The following components are not covered in this section.
Section 10 Inspection and Reconditioning Inspect the crankshaft bearing surfaces for scoring, grooving, etc. Measure the running clearance between the crankshaft journals and their respective bearing bores. Use an inside micrometer or telescoping gauge to measure the inside diameter of both bearing bores in the vertical and horizontal planes. Use an outside micrometer to measure the outside diameter of the crankshaft main bearing journals.
Section 10 Inspection and Reconditioning Crankcase Inspection and Service Check all gasket surfaces to make sure they are free of gasket fragments. Gasket surfaces must also be free of deep scratches or nicks. Check the cylinder bore for scoring. In severe cases, unburned fuel can cause scuffing and scoring of the cylinder wall. It washes the necessary lubricating oils off the piston and cylinder wall. As raw fuel seeps down the cylinder wall, the piston rings make metal to metal contact with the wall.
Section 10 Inspection and Reconditioning 4. After resizing, check the bore for roundness, taper, and size. Use an inside micrometer, telescoping gauge, or bore gauge to take measurements. The measurements should be taken at three locations in the cylinder – at the top, middle, and bottom. Two measurements should be taken (perpendicular to each other) at each of the three locations.
Section 10 Inspection and Reconditioning Carefully inspect the valve mechanism parts. Inspect the valve springs and related hardware for excessive wear or distortion. Check the valves and valve seat area or inserts for evidence of deep pitting, cracks, or distortion. Check clearance of the valve stems in the guides. See Figure 10-6 for valve details and specifications. Figure 10-5. Checking Cylinder Head Flatness.
Section 10 Inspection and Reconditioning Normal: Even after long hours of operation a valve can be reconditioned and reused if the face and margin are in good shape. If a valve is worn to where the margin is less than 1/32" do not reuse it. The valve shown was in operation for almost 1000 hours under controlled test conditions. Leakage: A poor grind on face or seat of valve will allow leakage resulting in a burned valve on one side only. Coking: Coking is normal on intake valves and is not harmful.
Section 10 Inspection and Reconditioning Excessive Combustion Temperatures: The white deposits seen here indicate very high combustion temperatures, usually due to a lean fuel mixture. Gum: Gum deposits usually result from using stale gasoline. Gum is a prevalent cause of valve sticking. The cure is to ream the valve guides and clean or replace the valves, depending on their condition. Stem Corrosion: Moisture in fuel or from condensation are the most common causes of valve stem corrosion.
Section 10 Inspection and Reconditioning Valve Guides If a valve guide is worn beyond specifications, it will not guide the valve in a straight line. This may result in burnt valve faces or seats, loss of compression, and excessive oil consumption. To check valve guide-to-valve stem clearance, thoroughly clean the valve guide and, using a splitball gauge, measure the inside diameter of the guide.
Section 10 Inspection and Reconditioning Ring failure is usually indicated by excessive oil consumption and blue exhaust smoke. When rings fail, oil is allowed to enter the combustion chamber where it is burned along with the fuel. High oil consumption can also occur when the piston ring end gap is incorrect because the ring cannot properly conform to the cylinder wall under this condition. Oil control is also lost when ring gaps are not staggered during installation.
Section 10 Inspection and Reconditioning Replacement pistons are available in STD bore size, and 0.25 mm (0.010 in.), and 0.50 mm (0.020 in.) oversize. Replacement pistons include new piston ring sets and new piston pins. Replacement ring sets are also available separately for STD, 0.25 mm (0.010 in.), and 0.50 mm (0.020 in.) oversize pistons. Always use new piston rings when installing pistons. Never use old rings. Some important points to remember when servicing piston rings: 1.
Section 10 Inspection and Reconditioning Piston Ring Dykem Stripe End Gap Identification Mark Service replacement connecting rods are available in STD crankpin size and 0.25 mm (0.010 in.) undersize. The 0.25 mm (0.010 in.) undersized rods have an identification marking on the lower end of the rod shank. Always refer to the appropriate parts information to ensure that correct replacements are used.
Section 10 Inspection and Reconditioning Disassembly The governor gear must be replaced once it is removed from the oil pan. NOTE: The governor gear is held onto the shaft by small molded tabs in the gear. When the gear is removed from the shaft, these tabs are destroyed and the gear must be replaced. Therefore, remove the gear only if absolutely necessary. 1. Remove the regulating pin and governor gear assembly. See Figure 10-13. Reassembly 1.
Section 10 Inspection and Reconditioning Piston Spring Figure 10-16. Oil Pump, Oil Pickup, and Relief Valve (Original Style). Roll Pin Figure 10-18. Oil Pressure Relief Valve Piston and Spring. Reassembly 1. Install the pressure relief valve piston and spring. 2. Install the oil pickup to the oil pump body. Lubricate the O-Ring with oil and make sure it remains in the groove as the pickup is being installed. 3. Install the rotor. 4.
Section 10 Inspection and Reconditioning 5. After torquing, rotate the gear and check for freedom of movement. Make sure there is no binding. If binding occurs, loosen the screws, reposition the pump, retorque the hex flange screws and recheck the movement. Crankcase Breather System The breather system is designed to control the amount of oil in the head area and still maintain the necessary vacuum in the crankcase. Figure 10-20. Oil Separator.
Section 11 Reassembly Section 11 Reassembly General NOTE: Make sure the engine is assembled using all specified torque values, tightening sequences, and clearances. Failure to observe specifications could cause severe engine wear or damage. Always use new gaskets. Apply a small amount of oil to the threads of critical fasteners before assembly, unless a Sealant or Loctite® is specified or pre-applied. Make sure all traces of any cleaner are removed before the engine is assembled and placed into operation.
Section 11 Reassembly Figure 11-2. Installing Oil Seal in Crankcase. Figure 11-4. Installing Governor Cross Shaft Hitch Pin (6 mm Shaft). Install Governor Cross Shaft 1. Lubricate the governor cross shaft bearing surfaces in the crankcase with engine oil. 2. Slide the small lower washer onto the governor cross shaft and install the cross shaft from the inside of the crankcase. 3.
Section 11 Reassembly Install Crankshaft 1. Carefully slide the flywheel end of the crankshaft through the main bearing in the crankcase. See Figure 11-7. 1. Stagger the piston rings in the grooves until the end gaps are 120° apart. The oil ring rails should also be staggered. 2. Lubricate the cylinder bore, piston, and piston rings with engine oil. Compress the rings using a piston ring compressor. 3. Lubricate the crankshaft journals and connecting rod bearing surfaces with engine oil. 4.
Section 11 Reassembly Torque these to 22.7 N·m (200 in. lb.) 8 mm Straight Shank Torque these to 14.7 N·m (130 in. lb.) 8 mm Step-Down Torque these to 11.3 N·m (100 in. lb.) 6 mm Straight Shank Figure 11-12. Apply Camshaft Lubricant to Cam Lobes. 2. Position the timing mark of the crankshaft gear at the 12 o'clock position. Figure 11-10. Connecting Rod Bolts. 3. Turn the governor cross shaft clockwise until the lower end of the shaft contacts the cylinder.
Section 11 Reassembly Governor Gear Assembly Determining Camshaft End Play 1. Install the shim removed during disassembly onto the camshaft. 2. Position the camshaft end play checking tool on the camshaft. See Figure 11-14. The governor gear assembly is located inside the oil pan. If service was required, and the governor was removed, refer to the assembly procedures under ''Governor Gear Assembly'' in Section 10. Install Oil Seal in Oil Pan 1.
Section 11 Reassembly Install Oil Pan Assembly RTV sealant is used as a gasket between the oil pan and the crankcase on CV17-23 engines. CV25-750 engines use an oil pan gasket. Refer to Section 2 for a listing of approved sealants. Always use fresh sealant. Using outdated sealant can result in leakage. 6. Install the ten hex flange screws securing the oil pan to the crankcase. Torque the fasteners in the sequence shown in Figure 11-18 to 24.4 N·m (216 in. lb).
Section 11 Reassembly Install Flywheel WARNING: Damaging Crankshaft and Flywheel Can Cause Personal Injury! Using improper procedures to install the flywheel can crack or damage the crankshaft and/or flywheel. This not only causes extensive engine damage, but can also cause personal injury, since broken fragments could be thrown from the engine. Always observe and use the following precautions and procedures when installing the flywheel. Figure 11-20. Torquing Stator Screws. 4.
Section 11 Reassembly NOTE: Make sure the flywheel key is installed properly in the keyway. The flywheel can become cracked or damaged if the key is not properly installed. 2. Install the flywheel onto the crankshaft being careful not to shift the woodruff key. See Figure 11-24. 3. Install the hex flange screw and washer. 4. Use a flywheel strap wrench or holding tool to hold the flywheel. Torque the hex flange screw securing the flywheel to the crankshaft to 66.4 N·m (49 ft. lb.). See Figure 11-25.
Section 11 Reassembly Figure 11-28. Installing Supports for Metal Grass Screen. 2. Tighten the supports with a torque wrench to 9.9 N·m (99 in. lb.). See Figure 11-29. The grass screen will be installed to the supports after the blower housing is in place. Figure 11-30. Applying Camshaft Lubricant to Bottom of Lifters. 3. Note the mark or tag identifying the hydraulic lifters as either intake or exhaust and cylinder 1 or cylinder 2.
Section 11 Reassembly Intake Valve Seal Figure 11-32. Match Numbers on Cylinder Barrel and Head. Figure 11-34. Intake Valve Seal Location. Assemble Cylinder Heads 4. If the breather reeds and stops were removed from the crankcase, reinstall them at this time and secure with the hex flange screw. Torque the screw to 4.0 N·m (35 in. lb.). See Figure 11-33.
Section 11 Reassembly Figure 11-36. Installing Valves with Valve Spring Compressor. Install Cylinder Heads NOTE: Cylinder heads must be attached with the original type of mounting hardware, using either hex flange screws, or mounting studs with nuts and washers. The heads are machined differently for studs than for screws, so the fastening method cannot be altered unless the heads are being replaced. Do not intermix the components. Figure 11-37. Torquing Cylinder Head Fasteners. 4.
Section 11 Reassembly b. Thread the opposite end of the stud, with the preapplied locking compound, into the crankcase, until the specified height from the crankcase surface is achieved. See Figure 11-39. When threading in the studs, use a steady tightening motion without interruption until the proper height is obtained. Otherwise the frictional heat from the engaging threads may cause the locking compound to set up prematurely.
Section 11 Reassembly 3. Install new plugs and torque to 24.4-29.8 N·m (18-22 ft. lb.). See Figure 11-44. Figure 11-42. Torquing Rocker Arm Screws. 4. Use a spanner wrench or rocker arm lifting tool (see Section 2), to lift the rocker arms and position the push rods underneath. See Figure 11-43. Figure 11-44. Installing Spark Plugs. Install Ignition Modules 1. Rotate the flywheel to position the magnet away from the ignition module bosses. Figure 11-43.
Section 11 Reassembly 4. Rotate the flywheel to position the magnet directly under one ignition module. 5. Insert a 0.30 mm (0.012 in.) flat feeler gauge between the magnet and the ignition module (see Figure 11-46). Loosen the screws enough to allow the magnet to pull the module against the feeler gauge. Figure 11-47. Installing Intake Manifold Gaskets. Figure 11-46. Setting Ignition Module Air Gap. 6. Torque the screws to 4.0-6.2 N·m (35-55 in. lb.). 7.
Section 11 Reassembly NOTE: If the wires were disconnected from the ignition modules on engines with SMARTSPARK™, reattach the leads and seal the base of the terminal connectors with GE/ Novaguard G661 (see Section 2) or Fel-Pro Lubri-Sel dielectric compound. The beads should overlap between the terminals* to form a solid bridge of compound. See Figure 11-50. Do not put any compound inside the terminals. *The 24 584 15-S ignition modules have a separator barrier between the terminals.
Section 11 Reassembly Install Blower Housing and Outer Baffles NOTE: Do not completely tighten screws until all items are installed to allow shifting for hole alignment. 1. Pull the wire harness and spark plug leads out through the appropriate openings in the shrouding. See Figures 11-57 and 11-58. Figure 11-54. Installing Screws (Locations 3 and 4). 4. Install the inner baffles using the remaining two hex flange screws (see Figures 11-55 and 11-56) and finger tighten.
Section 11 Reassembly Figure 11-59. Installing Blower Housing. 3. Position the outer baffles and secure using the four hex flange screws (two long, two short) in the front mounting holes (into cylinder head), including any lifting strap or attached bracket(s). Install the two short screws in the upper mounting holes of the outer baffles (into the backing plates). See Figures 11-60 and 11-61. Use the short screw on the left side to mount the wire harness bracket.
Section 11 Reassembly Install Oil Sentry™ (If So Equipped) 1. Apply pipe sealant with Teflon® (Loctite® No. 59241 or equivalent) to the threads of the Oil Sentry™ switch and install it into the breather cover. See Figure 11-63. Torque to 4.5 N·m (40 in. lb.). 2. Connect the wire lead (green) to the Oil Sentry™ terminal. Figure 11-63. Oil Sentry™ Switch (Some Models). Install Control Panel (If So Equipped) 1. Install the panel to the blower housing. 2.
Section 11 Reassembly Install Valve Covers Three valve cover designs have been used. The earliest type used a gasket and RTV sealant between the cover and sealing surface of the cylinder head. The second type had a black O-Ring installed in a groove on the underside of the cover and may have metal spacers in the bolt holes. The newest design uses a yellow or brown O-Ring, and the bolt hole spacers are molded in place. The tightening torque differs between gasket and O-Ring style covers.
Section 11 Reassembly Figure 11-67. Installing Carburetor, Throttle Linkage, and Governor Lever. Figure 11-70. Install Governor Lever to Shaft. 2. Make sure the throttle linkage is connected to the governor lever and the throttle lever on the carburetor. See Figure 11-71. Figure 11-68. Installing Two-Barrel Carburetor. Figure 11-71. Installing External Governor Controls (One-Barrel Carburetor).
Section 11 Reassembly Bushing Lever Choke Linkage Figure 11-72. Choke Linkage Details (Two-Barrel Models). Figure 11-74. Installing Lower Support Control Bracket. 7. Secure the control panel to the blower housing with the two screws (Models without a HeavyDuty Air Cleaner). See Figure 11-75. Figure 11-73. Throttle Linkage Details. 3. Move the governor lever toward the carburetor as far as it will go (wide-open throttle) and hold in position. 4.
Section 11 Reassembly 10. Connect the Oil Sentry™ Indicator light wires. Attach governor spring to governor lever. See Figure 11-76 and appropriate charts on pages 11.23 through 11.25. 2. One-Barrel Carburetor Models: Install the standard throttle control bracket and the air cleaner support bracket (if used) to the cylinder heads using the four hex flange screws. Torque the screws to 10.7 N·m (95 in. lb.) into new holes, or 7.3 N·m (65 in. lb.) into used holes. Figure 11-76.
Section 11 Reassembly Item 1 2 3 4 5 6 7 8 9 10 11 12 Description Bracket, speed control Clamp, cable (some applications) Kill Switch (some applications) Lever, choke (top position) Lever, throttle control (middle) Linkage, choke control Lever, throttle actuator (bottom) Screw, M5x0.8x20 Washer, wave Washer, flat (3) Spring, choke return Nut, M5x0.8 lock Figure 11-78. Throttle/Choke Control Bracket Detail. 3.
Section 11 Reassembly 8 mm Governor Lever and Hole Position/RPM Chart 4 3 2 1 Governor Lever CV18 Engines Intended Maximum RPM High Idle 3888 3780 3672 3564 3456 3348 3240 3132 3024 Standard Throttle Control Engine Mounted Throttle Control Pivot Shaft WOT Spring Color Hole No. Spring Color Hole No.
Section 11 Reassembly 8 mm Governor Lever and Hole Position/RPM Charts cont. CV26, CV745 EFI Engines Governor Shaft Configuration Standard (Parent Material) Intended Maximum RPM High Idle 3888 3780 3672 3564 3456 3348 3240 3132 3024 WOT Standard Throttle Control Spring Color 3600 3500 3400 3300 3200 3100 3000 2900 2800 Orange Black Red Green Red Green Blue Clear Clear Hole No. 3 3 3 2 2 1 1 1 1 With WAWB (Wide Area Walk Behind) Throttle Control Spring Color Hole No.
Section 11 Reassembly Install Fuel Pump WARNING: Explosive Fuel! Gasoline may be present in the carburetor and fuel system. Gasoline is extremely flammable and its vapors can explode if ignited. Keep sparks and other sources of ignition away from the engine. 1. Install the fuel pump and lines as an assembly. Connect the pulse line to the crankcase vacuum fitting. See Figures 11-81 and 11-82. NOTE: Fuel pumps may be made of metal or plastic.
Section 11 Reassembly Lower Screws Figure 11-84. Breather Hose and Separator Details. 2. Position a new gasket and the air cleaner base on the studs while carefully pulling the loose end of the rubber breather hose through the base until properly seated (collars sealed against each side of the base. See Figure 11-85. 3. Secure the air cleaner base and bracket, or spitback cup with baffle, using the hex flange nuts.
Section 11 Reassembly Install Muffler 1. Install the port liners (if equipped). Install the muffler and attaching hardware to the muffler bracket. Torque screws to 9.9 N·m (88 in. lb.). 2. Install the hex flange nuts to the exhaust studs. Torque hex flange nuts to 24.4. N·m (216 in. lb.). Install Oil Cooler If so equipped, the oil cooler can now be installed to the engine. Two different styles are used, see Section 6. Figure 11-88. Installing Upper Mounting Screws. 5.
Section 11 Reassembly Prepare the Engine for Operation The engine is now completely reassembled. Before starting or operating the engine, be sure to do the following. 1. Make sure all hardware is tightened securely. 2. Make sure the oil drain plugs, oil sentry pressure switch, and a new oil filter are installed. Drain Plug Figure 11-92. Install Oil Drain Plug(s). NOTE: Make sure that both oil drain plugs are installed and torqued to the above specifications to prevent oil leakage. 5.
FORM NO.: TP-2450-C ISSUED: 3/94 REVISED: 3/06 LITHO IN U.S.A. FOR SALES AND SERVICE INFORMATION IN U.S. AND CANADA, CALL 1-800-544-2444 ENGINE DIVISION, KOHLER CO.
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