Kohler Command CV17 Service Manual
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Kohler Command CV17 Service Manual

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S
M
ERVICE
ANUAL
COMMAND
CV17-750
V
C
ERTICAL
RANKSHAFT

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Summary of Contents for Kohler Command CV17

  • Page 1 ERVICE ANUAL COMMAND CV17-750 ERTICAL RANKSHAFT...

  • Page 2: Table Of Contents

    Section 1. Safety and General Information ... Section 2. Tools & Aids ... Section 3. Troubleshooting ... Section 4. Air Cleaner and Air Intake System ... Section 5. Fuel System and Governor ... Section 5B. Electronic Fuel Injection (EFI) Fuel System ... Section 6.

  • Page 3: Section 1. Safety And General Information

    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. WARNING Warning is used to indicate the presence of a hazard that can cause severe personal injury, death, or substantial property damage if the warning is ignored.
  • Page 4 Section 1 Safety and General Information WARNING Explosive Fuel can cause fires and severe burns. Do not fill the fuel tank while the engine is hot or running. Explosive Fuel! Gasoline is extremely flammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or flames.
  • Page 5 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. The engine identification numbers appear on a decal, or decals, affixed to the engine shrouding. See Figure 1-1.
  • Page 6 Gasoline/Alcohol blends Gasohol (up to 10% ethyl alcohol, 90% unleaded gasoline by volume) is approved as a fuel for Kohler 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 engines.
  • Page 7 ¹Perform these maintenance procedures more frequently under extremely dusty, dirty conditions. ²Only required for Denso starters. Not necessary on Delco starters. Have a Kohler Engine Service Dealer perform this service. ³Cleanout Kits 25 755 20-S (black) or 25 755 21-S (gold) allow cooling areas to be cleaned without removing shrouds.
  • Page 8 Section 1 Safety and General Information Figure 1-4. Typical Engine Dimensions CV Series with Standard Flat Air Cleaner. Dimensions in millimeters. Inch equivalents shown in [ ].
  • Page 9 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.
  • Page 10 Section 1 Safety and General Information Figure 1-6. Typical Engine Dimensions CV EFI Series with Heavy-Duty Air Cleaner. Dimensions in millimeters. Inch equivalents shown in [ ].
  • Page 11 General Specifications 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 ... 14.9 kW (20 HP) CV22 ... 16.4 kW (22 HP) CV23 ... 17.2 kW (23 HP) CV25,CV730 ...
  • Page 12 Section 1 Safety and General Information General Specifications 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 ...
  • Page 13 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 ... 8.025/8.075 mm (0.3159/0.3179 in.) Max. Wear Limit ... 8.088 mm (0.3184 in.) Breather Cover Fastener Torque ...
  • Page 14 Section 1 Safety and General Information Cylinder Bore Cylinder Bore I.D. New - CV17 ... 73.006/73.031 mm (2.8742/2.8752 in.) New - CV18,CV20,CV22 (624 cc) ... 77.000/77.025 mm (3.0315/3.0325 in.) New - CV22/23 (674 cc) ... 80.000/80.025 mm (3.1496/3.1506 in.) New - CV25,CV26,CV730-750 ... 82.988/83.013 mm (3.2672/3.2682 in.) Max.
  • Page 15 Ignition ® Spark Plug Type (Champion or Equivalent) ... RC12YC, XC12YC, or Platinum 3071 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 ... 0.28/0.33 mm (0.011/0.013 in.) Ignition Module Fastener Torque ...
  • Page 16 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) ... 0.25/0.45 mm (0.0098/0.0177 in.) New Bore - CV22 (674 cc) ...
  • Page 17 Stator Mounting Screw Torque ... 6.2 N·m (55 in. lb.) 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 ... 9.9 N·m (88 in. lb.) Yellow or Brown O-Ring Style Cover w/Integral Metal Spacers ...
  • Page 18 Section 1 Safety and General Information General Torque Values Metric Fastener Torque Recommendations for Standard Applications Tightening Torque: N·m (in. lb.) + or - 10% Size 1.2 (11) 1.7 (15) 2.5 (22) 3.2 (28) 4.3 (38) 5.7 (50) 10.5 (93) 13.6 (120) Tightening Torque: N·m (ft.
  • Page 19 English Fastener Torque Recommendations for Standard Applications Tightening Torque: N·m (in. lb.) + or - 20% Bolts, Screws, Nuts and Fasteners Assembled Into Cast Iron or Steel Grade 2 Size 8-32 2.3 (20) 10-24 3.6 (32) 10-32 3.6 (32) 1/4-20 7.9 (70) 1/4-28 9.6 (85)

  • Page 20: Section 2. Tools & Aids

    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. &...
  • Page 21 Section 2 Tools & Aids ) . t . l a t f i l l a c i l f i l i t i & l i o i f i i f i i f i . s r a l i l a i l l a...
  • Page 22 - l e i l i ® e t i l i o s i s ® e t i e t i ® ® e t i ® e t i e t i ® ) t f . r e , s t s i l s i r...
  • Page 23 4. Use a flat washer with the correct I.D. to slip on the capscrew and approximately 1” O.D. (Kohler Part No. 12 468 05-S). Assemble the capscrew and washer to the joint surface of the rod, as shown in Figure 2-2.

  • Page 24: 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.
  • Page 25 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.
  • Page 26 • 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...
  • Page 27 Section 3 Troubleshooting No Crankcase Vacuum/Pressure in Crankcase Possible Cause 1. Crankcase breather clogged or inoperative. 2. Seals and/or gaskets leaking. Loose or improperly torqued fasteners. 3. Piston blowby or leaky valves (confirm by inspecting components). 4. Restricted exhaust. Compression Test Some of these engines are equipped with an automatic compression release (ACR) mechanism.
  • Page 28 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 ...Piston rings and cylinder in good condition. Gauge reading in “moderate”...

  • Page 29: Section 4. Air Cleaner And Air Intake System

    Air Cleaner and Air Intake System Air Cleaners General These engines are equipped with a replaceable, high- density 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.
  • Page 30 4. Do not wash the paper element or use pressurized air, as this will damage the element. Replace a dirty, bent, or damaged element with a Precleaner genuine Kohler element. Handle new elements carefully; do not use if the sealing surfaces are bent or damaged. Element 5.
  • Page 31 Rubber Seal Air Cleaner Cover Knob Seal Element Cover Nut Knob Figure 4-5. Air Cleaner System Components - Standard. *Plenum air cleaner system does not use a precleaner. Wing Nut Air Cleaner Cover (Plenum*) Cover Retaining Knob Figure 4-6. Air Cleaner System Components - Commercial Mower Type. Air Cleaner and Air Intake System Spitback Cup Precleaner...
  • Page 32 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.
  • Page 33 4. Do not wash the paper element and inner element or use compressed air, this will damage the elements. Replace dirty, bent or damaged elements with new genuine Kohler elements as required. Handle the new elements carefully; do not use if the sealing surfaces are bent or damaged.
  • Page 34 Make sure the cooling shrouds are reinstalled. *Cleanout kits, Kohler Part No. 25 755 20-S (black) or 25 755 21-S (gold), are recommended to aid inspection and cleanout of the cooling fins. See Figure 4-11.

  • Page 35: Section 5. Fuel System And Governor

    Gasoline/Alcohol blends Gasohol (up to 10% ethyl alcohol, 90% unleaded gasoline by volume) is approved as a fuel for Kohler 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 engines.
  • Page 36 (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. Order replacement hose by part number through a Kohler Engine Service Dealer. IMPORTANT ENGINE INFORMATION THIS ENGINE MEETS U.S.
  • Page 37 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 –...
  • Page 38 Section 5 Fuel System and Governor Fuel Pump 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.
  • Page 39 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.
  • Page 40 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.
  • Page 41 Troubleshooting – Carburetor Related Causes Condition 1. Engine starts hard, runs roughly or stalls at idle speed. 2. Engine runs rich (indicated by black, sooty exhaust smoke, misfiring, loss of speed and power, governor hunting, or excessive throttle opening). 3. Engine runs lean (indicated by misfiring, loss of speed and power, governor hunting, or excessive throttle opening).
  • Page 42 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 over- rich. 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.
  • Page 43 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 Speed (RPM) Adjustment Figure 5-6. Carburetor Adjustments. 2.
  • Page 44 Section 5 Fuel System and Governor Governed Idle Spring 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). Carburetor Servicing (CV17-740) Nikki Carburetors Float Replacement If symptoms described in the carburetor troubleshooting guide indicate float level problems, remove the carburetor from the engine to check and/or replace the float.
  • Page 45 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.
  • Page 46 Section 5 Fuel System and Governor Figure 5-10. Typical Carburetor - Exploded View. Inspection/Repair To clean vent ports, seats etc., use a good commercially available carburetor solvent, such as Gumout™, and clean, dry compressed air to blow out internal channels and ports. Use a suitable shop rag to prevent debris from hitting someone.
  • Page 47 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...
  • Page 48 Section 5 Fuel System and Governor 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. The inlet needle should be fully seated but the center pin of the needle (on retainer clip end) should not be depressed.
  • Page 49 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.
  • Page 50 Section 5 Fuel System and Governor Figure 5-21. Installing Slow Jet. Figure 5-22. Installing Plug into Slow Jet Tube. 10. Attach the inlet needle to the metal tang of the float with the wire clip. The formed 90° lip of the metal tang should point up, with the needle valve hanging down.
  • Page 51 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 5-26. Installing Fuel Bowl O-Rings. 15. Install the fuel bowl onto the carburetor. Secure with the four original screws.
  • Page 52 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 5-30. Accelerator Pump Cover and Diaphragm Removed. 3. Remove the retaining ring over the rubber check valve, using a snap ring pliers.
  • Page 53 Figure 5-34. Installing Accelerator Pump Housing Screws and Hose. 8. Install the new clips onto each end of the new vacuum hose, and connect the hose onto the fittings. See Figure 5-34. Discard all the old parts. Choke Repair 1. Remove the carburetor from the engine. Discard the old mounting gaskets for the air cleaner and carburetor.
  • Page 54 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.
  • Page 55 Adjustment NOTE: Carburetor adjustments should be made only after the engine has warmed up. The carburetor is designed to deliver the correct fuel- to-air mixture to the engine under all operating conditions. The main fuel jet is calibrated at the factory and is not adjustable*.
  • Page 56 Section 5 Fuel System and Governor Lean Adjust to Adjust to Midpoint Midpoint Rich Rich Left Side Figure 5-40. Optimum Low Idle Fuel Settings. 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.
  • Page 57 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.
  • Page 58 Section 5 Fuel System and Governor 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.
  • Page 59 Main Nozzles 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.
  • Page 60 Section 5 Fuel System and Governor Nozzle End with Two Shoulders (Out/Down) 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.
  • Page 61 Figure 5-58. Checking Float Height. NOTE: Be sure to measure from the casting surface, not the rubber gasket, if still attached. 16. 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.
  • Page 62 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.
  • Page 63 Figure 5-65. Keihin BK Two-Barrel Carburetor - Exploded View. Section 5 Fuel System and Governor 1. Carburetor Body Subassembly 2. Idle Speed Screw 3. Idle Speed Spring 4. Screw 5. Ground Lead 6. Retaining Washer 7. Slow Jet - RH Side 8.
  • Page 64 Section 5 Fuel System and Governor Governor 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.
  • Page 65 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.
  • Page 66 Section 5 Fuel System and Governor Choke Lever Detail Choke Cable Control Bracket Blower Housing Washer Spring Clip Lever Spring Figure 5-68. Governor Used with Commercial Mower Air Cleaner (CV17-745). Commercial Mower Governor Arrangement The Commercial Mower governor arrangement shown in Figure 5-68 is used primarily on wide area walk behind mower applications.
  • Page 67 Screw Washer Spring Washer Spacer Lock Nut Bushing Choke Linkage Figure 5-69. Governor/Controls Assembly (CV750). Hex Nut Screw Choke Cable Clamp and Screw Control Bracket Screw Washer Spring Linkage Spring Governor Lever Governor Spring Washer Spacer Lock Nut Section 5 Fuel System and Governor Throttle Control Lever Lock Nut...
  • Page 68 Electronic Fuel Injection (EFI) Contents Description Initial Starting/Priming Procedure ... 5B.2 Fuel Recommendations ... 5B.2-5B.3 EFI Fuel System Components ... 5B.3 Operation ... 5B.3 Important Service Notes ... 5B.4 Electrical Components Electronic Control Unit (ECU) ... 5B.4-5B.5 Engine Speed Sensor ... 5B.5-5B.6 Throttle Position Sensor (TPS) and Initialization Procedures ...
  • Page 69 Section 5B EFI Fuel System Description WARNING Explosive Fuel can cause fires and severe burns. Fuel system ALWAYS remains under HIGH PRESSURE. WARNING: Explosive Fuel! Gasoline is extremely flammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or flames.
  • Page 70 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.

  • Page 71: Electrical Components

    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.
  • Page 72 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.
  • Page 73 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 ±...
  • Page 74 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.
  • Page 75 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. a. Repair or replace as required. b. Turn the idle speed screw back in to its original setting.
  • Page 76 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”...
  • Page 77 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.
  • Page 78 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.
  • Page 79 Section 5B EFI Fuel System b. If the resistance is less than 1.0 MΩ Ω Ω Ω Ω , the 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.
  • Page 80 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.
  • Page 81 Section 5B EFI Fuel System 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.
  • Page 82 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.
  • Page 83 Section 5B EFI Fuel System 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. Remove the air cleaner outer cover, inner wing nut, element cover and air cleaner element/ precleaner.
  • Page 84 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.
  • Page 85 EFI Fuel System Spark Plugs EFI engines are equipped with Champion (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.
  • Page 86 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.
  • Page 87 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.
  • Page 88 6. Install the new regulator by carefully pushing and rotating it slightly into the base or housing. 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. b.
  • Page 89 60” of high-pressure hose and 10 Oetiker clamps), or use only the type of hose specified. Special Oetiker clamps (Kohler Part No. 24 237 05-S) are used on all fuel line connections to prevent tampering and safety hazards with the high fuel pressure. The old clamp must be cut to open a connection, so replacement is necessary each time.
  • Page 90 Idle Speed Screw Figure 5B-33. Idle Speed Screw Details. Initial Governor Adjustment The initial governor adjustment is especially critical on EFI engines because of the accuracy and sensitivity of the electronic control system. Incorrect adjustment can result in overspeed, loss of power, lack of response, or inadequate load compensation.
  • Page 91 Section 5B EFI Fuel System Figure 5B-36. Inserting Feeler Gauge (Engines Without Stop Screw). b. On engines without a stop screw, pivot the throttle shaft and plate assembly into the “Full Throttle” position. Insert a 1.52 mm (0.060 in.) feeler gauge between the tang of the throttle shaft plate and the underside of the manifold boss.

  • Page 92: Troubleshooting

    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’’.
  • Page 93 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.
  • Page 96 “32 Pin” (MSE 1.1) Plastic-Cased ECU Systems Pin # Permanent Battery Voltage Switched Battery Voltage TPS Set; “Auto-Learn” Initialization Terminal Throttle Position Sensor (TPS) and Temperature Sensor Ground Not Used Oil Temperature Sensor Input Not Used Throttle Position Sensor (TPS) Input Speed Sensor Input (+) Speed Sensor Ground (-) Not Used...
  • Page 97 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.
  • Page 98 Example of Diagnostic Display 1. Diagnostic display initiated through ignition key sequencing. Long Pause Figure 5B-40. 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.
  • Page 99 Section 5B EFI Fuel System Diagnostic Code Summary cont. c i l 3 " " n i n i u l i u l i Note: 1. Idle Switch not used. 2. Diagnostic of "TPS - Signal Implausible" is disabled in code. 3.
  • Page 100 Code: Source: Engine Speed Sensor Explanation: 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.
  • Page 101 Section 5B EFI Fuel System Code: Source: Explanation: 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.
  • Page 102 Code: Source: Oxygen Sensor/Fuel System Explanation: “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.
  • Page 103 Section 5B EFI Fuel System Code: 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.
  • Page 104 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.
  • Page 105 Section 5B EFI Fuel System Code: Source: Explanation: Denotes the end of fault codes. If signaled first, no other fault codes are present. 5B.38 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.
  • Page 106 Section 5B EFI Fuel System *Operate for an appropriate period of time based upon original fault codes. Figure 5B-41. 5B.39...
  • Page 107 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”...
  • Page 108 Diagnostic Aid #5 “FUEL PUMP” (fuel pump not turning on) 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.

  • Page 109: Section 6. Lubrication System

    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.
  • Page 110 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.
  • Page 111 Replace the oil filter at least every other oil change (every 200 hours of operation). Always use a genuine Kohler oil filter. Change the filter as follows. See Figures 6-4 or 6-5. 1. An oil drain plug is located on either side of the oil sump;...
  • Page 112 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.

  • Page 113: Section 7. Retractable Starter

    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. Starter Housing Flange Screws Spring and Keeper Pulley...
  • Page 114 Section 7 Retractable Starter 6. Tie a single knot in one end of the new rope. 7. Rotate the pulley counterclockwise (when viewed from pawl side of pulley) until the spring is tight (approximately 6 full turns of pulley). 8. Rotate the pulley clockwise until the rope hole in the pulley is aligned with the rope guide bushing of the starter housing.
  • Page 115 2. Replace all worn or damaged components. Use only genuine Kohler replacement parts as specified in the Parts Manual. All components shown in Figure 7-1 are available as service parts. Do not use nonstandard parts.
  • Page 116 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. 4. Clean all old grease and dirt from the starter components. Generously lubricate the spring and center shaft with any commercially available bearing grease.

  • Page 117: Section 8. Electrical System And Components

    The engine is equipped with the following spark plugs: Type: The standard spark plug is a Champion RC12YC (Kohler Part No. 12 132 02-S). RFI compliant engines use a Champion (Kohler 25 132 14-S) spark plug. A high- performance spark plug, Champion 3071 (used on Pro Series engines, Kohler Part No.
  • Page 118 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.
  • Page 119 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.
  • Page 120 Section 8 Electrical System and Components Electronic CD Ignition Systems Starter and Ignition Carburetor Module Solenoid Input Input B+ and Carburetor Solenoid Input Violet Figure 8-3. Electronic CD Ignition System (For Customer Connected Tractor Applications). The SMART-SPARK ignition system used on some ™...
  • Page 121 Kill Switch or ‘‘Off’’ Position of Key Switch 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. Figure 8-5. Capacitive Discharge Ignition Module Schematic. Operation: As the flywheel rotates, the magnet grouping passes the input coil (L1).
  • Page 122 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: •...
  • Page 123 Because you have interrupted the kill circuit, it may not stop using the switch. 2. Test for spark on both cylinders with Kohler ignition tester (see Section 2). Disconnect one spark plug lead and connect it to the post terminal of the tester.
  • Page 124 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.
  • Page 125 All modules with vendor part numbers MA-2, MA-2A, or MA-2B (Kohler Part No. 24 584 03) should be replaced with 24 584 11 or 24 584 15-S. For small modules with vendor numbers MA-2C or MA-2D (Kohler Part No.
  • Page 126 Section 8 Electrical System and Components Ignition Module Resistance Table 24 584 03 or 24 584 11 (1 11/16 in. High) 5. Check and/or adjust the ignition module air gap(s). An air gap of 0.28/0.33 mm (0.011/0.013 in.) must be maintained under all three legs of the ignition module(s).
  • Page 127 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.
  • Page 128 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.
  • Page 129 To Test – Using 25 761 40-S Tester DSAM/ASAM Test Procedure NOTE: The SAM must be at room temperature when tested. Disconnect all of the SAM leads, isolating it from the main wiring harness and the ignition module(s). Testing may be performed with the module mounted or loose.
  • Page 130 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.
  • Page 131 Section 8 Electrical System and Components 15/20/25 Amp Regulated Charging System Figure 8-17. Wiring Diagram - 15/20/25 Amp Regulated Battery Charging System with Fixed Timing. 8.15...
  • Page 132 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.
  • Page 133 1st Style 2nd Style Figure 8-21. 25 Amp Stator and Rectifier-Regulators. 3 Amp Unregulated Charging System Ground-To-Kill Lead (White) Light Keyswitch Optional Oil Sentry Switch (Indicator Light) Optional Oil Sentry Switch (Shutdown) 12 V. Battery Figure 8-22. Wiring Diagram - 3 Amp Unregulated Battery Charging System/70 Watt Lighting. Electrical System and Components (Blue) (Red)

  • Page 134: Section 9. Disassembly

    Section 8 Electrical System and Components Lighting Lead (Yellow) Diode Charging Lead (Black) 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.
  • Page 135 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.
  • Page 136 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.
  • Page 137 Figure 8-32. 3. Plug the tester into the proper AC outlet/power supply for tester being used. Turn on the power switch. The ‘‘POWER’’ light should be illuminated and one of the four status lights may be on as well. See Figure 8-26. This does not represent the condition of the part.

  • Page 138: Troubleshooting Guide

    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.
  • Page 139 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 1.
  • Page 140 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.
  • Page 141 4. Clean the splines on the drive shaft thoroughly with solvent. Dry the splines thoroughly. 5. Apply a small amount of Kohler electric starter drive lubricant, (see Section 2) to the splines. The use of other lubricants may cause the drive pinion to stick or bind.
  • Page 142 If the splines are dirty, clean them with solvent. 7. The splines should have a light film of lubricant. Relubricate as necessary with Kohler starter drive lubricant (see Section 2). Reinstall or replace the drive components, assembling them in the...
  • Page 143 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.
  • Page 144 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. Self- Brush Springs Tapping Screw Negative (-) Brush Stud Terminal with Positive (+) Brushes...
  • Page 145 Figure 8-42. Style ‘‘B’’ Commutator End Cap with Brushes. 6. Install the thru bolts and tighten securely. 7. Lubricate the drive shaft with Kohler starter drive lubricant (see Section 2). Install the drive components following the instructions for servicing the starter drive.
  • Page 146 Brush Replacement The brushes in the starter are part of the starter frame. Brush kit, Kohler Part No. 52 221 01-S, contains four replacement brushes and springs. If replacement is necessary, all four brushes should be replaced.
  • Page 147 Phillips Head Screws Torx Head Screws Figure 8-45. Removing Solenoid Screws. 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.
  • Page 148 Section 8 Electrical System and Components 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 8-49. Removing Commutator End Plate Assembly.
  • Page 149 Figure 8-53. Retaining Ring Detail. 11. Remove the retainer from the armature shaft. Save the stop collar. NOTE: Do not reuse the old retainer. Collar Ring Stop Drive Armature Washer Tube Figure 8-55. Delco-Remy Starter. Electrical System and Components Figure 8-54. Removing Retaining Ring. 12.
  • Page 150 Section 8 Electrical System and Components Inspection 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.
  • Page 151 Brush Replacement 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. 1. Perform steps 1-5 in “Starter Disassembly.” 2. Remove the two screws securing the brush holder assembly to the end cap (plate).
  • Page 152 Section 8 Electrical System and Components 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. Lubricate the fork end and center pivot of the drive lever with drive lubricant (see Section 2).
  • Page 153 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.
  • Page 154 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.
  • Page 155 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.
  • Page 156 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.
  • Page 157 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.
  • Page 158 Section 9 Disassembly Figure 9-2. Removing Oil Fill Cap/Dipstick. Figure 9-3. Removing Oil Fill Tube Bracket. Figure 9-4. Removing Oil Filter. 2. Allow ample time for the oil to drain from the crankcase and oil filter. 3. Remove the mounting screw and detach the oil fill tube.
  • Page 159 Figure 9-6. Removing Standard Element and Precleaner. 3. Remove the element cover, element and precleaner. See Figure 9-6. Hex Flange Nuts (2) Lower Mounting Screws (Some Models) 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.
  • Page 160 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. Adapter Elbow Breather Hose Figure 9-10.
  • Page 161 Figure 9-14. Removing Throttle Control Bracket. Figure 9-15. Removing Control Panel. 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. Keep sparks, open flames and other sources of ignition away from the engine.
  • Page 162 Section 9 Disassembly Control Bracket Figure 9-18. Removing Control Bracket. Air Cleaner Brackets (Some Models) Control Bracket Figure 9-19. Removing Control Bracket and Air Cleaner Bracket (Some Models). 2. Disconnect the spring from the governor lever; note hole locations for reassembly. 3.
  • Page 163 3. Remove the carburetor, throttle linkage and governor lever as an assembly. Figure 9-22. Removing Carburetor and Linkage (Two-Barrel Model Pictured). Figure 9-23. Removing Carburetor Mounting Nuts (Commercial Mower Base Shown). Figure 9-24. Removing Carburetor. 4. Remove the carburetor gasket. 5.
  • Page 164 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.
  • Page 165 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. Ground Strap Silver Screw Figure 9-31.
  • Page 166 Section 9 Disassembly Figure 9-35. Break Breather Cover Seal. 5. Remove the breather cover and gasket (if used). See Figure 9-36. Figure 9-36. 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.
  • Page 167 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.
  • Page 168 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.
  • Page 169 Figure 9-45. Removing Rocker Arm. 2. Compress the valve springs using a valve spring compressor. See Figure 9-46. Figure 9-46. Removing Valves with Valve Spring Compressor. 3. Once the valve spring is compressed, remove the following items. See Figures 9-47 and 9-48: •...
  • Page 170 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 9-50. Removing Fan. Remove Flywheel 1. Use a flywheel strap wrench or holding tool (see Section 2) to hold the flywheel and loosen the hex flange screw securing the flywheel to the crankshaft.
  • Page 171 Figure 9-53. Removing Backing Plates and Stator Wire Bracket. 2. Remove the two hex flange screws and the stator. See Figure 9-54. Note the position/routing of the stator lead. Figure 9-54. Removing Stator. Remove Oil Pan Assembly 1. Remove the ten hex flange screws securing the oil pan to the crankcase.
  • Page 172 Section 9 Disassembly Figure 9-57. Removing Governor Cross Shaft Hitch Pin (6 mm Shaft Design). Figure 9-58. Removing Governor Cross Shaft Retainer (8 mm Shaft Design). 2. Remove the cross shaft through the inside of the crankcase. See Figure 9-59. Figure 9-59.
  • Page 173 3. Repeat the above procedure for the other connecting rod and piston assembly. Remove Crankshaft 1. Carefully pull the crankshaft from the crankcase. See Figure 9-62. Figure 9-62. Removing Crankshaft. Remove Flywheel End Oil Seal 1. Remove the oil seal from the crankcase. See Figure 9-63.

  • Page 174: Section 10. Inspection And Reconditioning

    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. They are covered in sections of their own: Air Cleaner, Section 4 Carburetor & External Governor, Section 5 Ignition, Charging &...
  • Page 175 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.
  • Page 176 Move the hone up and down while resizing to prevent the formation of cutting ridges. Check the size frequently. NOTE: Kohler pistons are custom-machined to exacting tolerances. When oversizing a cylinder, it should be machined exactly 0.25 mm (0.010 in.) or 0.50 mm (0.020 in.) over the new diameter (Section 1).
  • Page 177 Replace the flywheel, the crankshaft, and the key if the flywheel key is sheared or the keyway is damaged. Inspect the ring gear for cracks or damage. Kohler does not provide ring gears as a serviceable part. Replace the flywheel if the ring gear is damaged.
  • Page 178 Figure 10-5. Checking Cylinder Head Flatness. EXHAUST VALVE Dimension 89° Seat Angle 36.987/37.013 mm (1.4562/1.4572 in.) Insert O.D. 4 mm (0.1575 in.) Guide Depth 7.038/7.058 mm (0.2771/0.2779 in.) Guide I.D. 33.37/33.63 mm (1.3138/1.3240 in.) Valve Head Diameter 45° Valve Face Angle 1.5 mm (0.0591 in.) Valve Margin (Min.) 6.982/7.000 mm (0.2749/0.2756 in.)
  • Page 179 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.
  • Page 180 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.
  • Page 181 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 split- ball gauge, measure the inside diameter of the guide.
  • Page 182 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.
  • Page 183 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.
  • Page 184 Check the base surface of the hydraulic lifters for wear or damage. If the lifters need to be replaced, apply a liberal coating of Kohler lubricant (see Section 2) to the base of each new lifter before it is installed.

  • Page 185: Section 11. Reassembly

    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.
  • Page 186 Figure 10-16. Oil Pump, Oil Pickup, and Relief Valve (Original Style). Figure 10-17. Oil Pump, Plastic Oil Pickup, and One-Piece Relief Valve (Later Style). Inspection Inspect the oil pump housing, gear, and rotors for nicks, burrs, wear, or any visible damage. If any parts are worn or damaged, replace the oil pump.
  • Page 187 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...
  • Page 188 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 ®...
  • Page 189 Section 11 Reassembly Figure 11-2. Installing Oil Seal in Crankcase. 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.
  • Page 190 Install Crankshaft 1. Carefully slide the flywheel end of the crankshaft through the main bearing in the crankcase. See Figure 11-7. Figure 11-7. Installing Crankshaft. Install Connecting Rods with Pistons and Rings NOTE: The cylinders are numbered on the crankcase. Make sure to install the piston, connecting rod, and end cap into its appropriate cylinder bore as previously marked at disassembly.
  • Page 191 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 11-10. Connecting Rod Bolts. Figure 11-11.
  • Page 192 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. Figure 11-14. Checking Camshaft End Play. 3. Apply pressure on the camshaft end play checking tool (pushing camshaft toward crankshaft).
  • Page 193 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.
  • Page 194 Figure 11-20. Torquing Stator Screws. 4. Route the stator leads in the crankcase channel, then install the backing plates and stator wire bracket (if used). Secure with the four hex flange screws. See Figures 11-21 and 11-22. Torque the screws to 7.3 N·m (65 in. lb.). Figure 11-21.
  • Page 195 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.
  • Page 196 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 11-29.
  • Page 197 Section 11 Reassembly Figure 11-32. Match Numbers on Cylinder Barrel and Head. 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. Figure 11-33.
  • Page 198 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.
  • Page 199 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.
  • Page 200 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 11-43. Using Spanner Wrench to Lift Rocker Arm Over Push Rod.
  • Page 201 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.
  • Page 202 NOTE: If the wires were disconnected from the ignition modules on engines with SMART- SPARK , 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.
  • Page 203 Section 11 Reassembly 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. Do not torque the screws at this time; they will be tightened after the blower housing and outer baffles are installed.
  • Page 204 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).
  • Page 205 Section 11 Reassembly Install Oil Sentry™ (If So Equipped) 1. Apply pipe sealant with Teflon 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.
  • Page 206 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.
  • Page 207 Section 11 Reassembly Figure 11-67. Installing Carburetor, Throttle Linkage, and Governor Lever. Figure 11-68. Installing Two-Barrel Carburetor. Figure 11-69. Installing External Governor Controls. Install External Governor Controls 1. Install the governor lever onto the governor cross shaft. See Figure 11-70. 11.20 Figure 11-70.
  • Page 208 Bushing Lever Figure 11-72. Choke Linkage Details (Two-Barrel Models). 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. Insert a nail into the hole on the cross shaft and rotate the shaft counterclockwise as far as it will turn, then torque the hex nut to 6.8 N·m (60 in.
  • Page 209 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. Figure 11-76. Connecting Governor Spring to Governor Lever. Install Throttle and Choke Controls 1.
  • Page 210 Item 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.
  • Page 211 Section 11 Reassembly 8 mm Governor Lever and Hole Position/RPM Chart CV18 Engines Intended Maximum RPM High Idle 3888 3600 3780 3500 3672 3400 3564 3300 3456 3200 3348 3100 3240 3000 3132 2900 3024 2800 CV20-740 Engines with 0.0299 + 0.003 in. Thick (22 GA) Throttle Limiter Intended Maximum RPM High Idle...
  • Page 212 8 mm Governor Lever and Hole Position/RPM Charts cont. CV26, CV745 EFI Engines Intended Governor Shaft Maximum RPM Configuration High Idle 3888 3780 3672 Standard 3564 (Parent Material) 3456 3348 3240 3132 3024 CV750 Engines Intended Governor Shaft Maximum RPM Configuration High Idle 3888...
  • Page 213 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.
  • Page 214 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.
  • Page 215 Section 11 Reassembly Figure 11-88. Installing Upper Mounting Screws. 5. Torque the valve cover/mounting bracket screws to the proper specification and torque sequence listed under “Install Valve Covers” on page 11.19. Figure 11-89. Securing Air Cleaner Mounting Bracket. 6. Two-Barrel Carburetor Models Only: Attach the choke return spring to the bottom of the main control bracket.
  • Page 216 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. Add oil to bring the level up to the ‘‘Full’’ mark and reinstall the dipstick.
  • Page 217 FOR SALES AND SERVICE INFORMATION IN U.S. AND CANADA, CALL 1-800-544-2444 ENGINE DIVISION, KOHLER CO., KOHLER, WISCONSIN 53044 FORM NO.: TP-2450-C ISSUED: 3/94 REVISED: 3/06 LITHO IN U.S.A.

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