Kohler command pro ECH749 Service Manual
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Kohler command pro ECH749 Service Manual

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ECH630-ECH749, CH735, CH26, CH745
Service Manual
IMPORTANT:
Read all safety precautions and instructions carefully before operating equipment. Refer to operating
instruction of equipment that this engine powers.
Ensure engine is stopped and level before performing any maintenance or service.
2
Safety
3
Maintenance
5
Specifi cations
22
Tools and Aids
25
Troubleshooting
29
Air Cleaner/Intake
30
Electronic Fuel Injection (EFI) System-ECH
59
Electronic Fuel Injection (EFI) System-Bosch
92
94
99
103
122
Reassembly
24 690 01 Rev. K
KohlerEngines.com
1

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Summary of Contents for Kohler command pro ECH749

  • Page 1 ECH630-ECH749, CH735, CH26, CH745 Service Manual IMPORTANT: Read all safety precautions and instructions carefully before operating equipment. Refer to operating instruction of equipment that this engine powers. Ensure engine is stopped and level before performing any maintenance or service. Safety Maintenance Specifi...
  • Page 2 Safety SAFETY PRECAUTIONS WARNING: A hazard that could result in death, serious injury, or substantial property damage. CAUTION: A hazard that could result in minor personal injury or property damage. NOTE: is used to notify people of important installation, operation, or maintenance information. CAUTION WARNING WARNING...
  • Page 3 Perform these procedures more frequently under severe, dusty, dirty conditions. REPAIRS/SERVICE PARTS Kohler genuine service parts can be purchased from Kohler authorized dealers. To fi nd a local Kohler authorized dealer visit KohlerEngines.com or call 1-800-544-2444 (U.S. and Canada). 24 690 01 Rev. K...
  • Page 4 OIL RECOMMENDATIONS STORAGE If engine will be out of service for 2 months or more We recommend use of Kohler oils for best performance. follow procedure below. Other high-quality detergent oils (including synthetic) of API (American Petroleum Institute) service class SJ 1.
  • Page 5 Specifi cations Engine Dimensions with Heavy-Duty Air Cleaner-Flywheel Side 342.52 mm Valve Cover 451.16 mm (17.762 in.) Fuel Pump (13.485 in.) 88.28 mm 298.93 mm 230.20 mm (9.063 in.) 130.0 mm (5.118 in.) (3.475 in.) (11.769 in.) 77.17 mm 67.19 mm 277.22 mm (10.914 in.) 135.0 mm (5.315 in.) (3.038 in.) Spark Plug...
  • Page 6 Specifi cations Engine Dimensions with Heavy-Duty Air Cleaner-Oil Filter Side 30.0 mm (1.181 in.) 371.44 mm 209.88 mm (8.263 in.) 52.43 mm (2.064 in.) Spark Plug Center (14.624 in.) Line 32.00 mm (1.260 in.) Oil Fill Dipstick 101.38 mm (3.992 in.) Exhaust Port #2 7/16-20 UNF-2B in.
  • Page 7 Specifi cations Engine Dimensions with Heavy-Duty Air Cleaner-PTO Side 65.0 mm (2.559 in.) 335.04 mm (13.19 in.) 122.10 mm (4.807 in.) 75.42 mm (2.969 in.) Muffl er Mounting 50.00 mm (1.969 in.) Lift Strap Oil Fill Location 30° Exhaust Port #2 5/16-24 UNC-2B in.
  • Page 8 Specifi cations Engine Dimensions with Heavy-Duty Air Cleaner-Starter Side 50.0 mm (1.969 in.) 67.50 mm (2.657 in.) 12.0 mm (0.472 in.) Center Line Spark Muffl er Mounting Dipstick Exhaust Port #1 Plug Bosses 432.58 mm Engine Mounting Center Line Mounting 89.0 mm (3.504 in.) (17.031 in.) Surface...
  • Page 9 Specifi cations Engine Dimensions with Low-Profi le Air Cleaner-Flywheel Side 451.16 mm (17.762 in.) 298.93 mm (11.769 in.) Valve Cover 12.95 mm (0.510 in.) 67.19 mm 77.17 mm 37.15 mm 473.43 mm (2.645 in.) Spark (3.038 in.) Spark (1.463 in.) Spark (18.639 in.) Plug Boot Removal Plug Removal...
  • Page 10 Specifi cations Engine Dimensions with Low-Profi le Air Cleaner-Oil Filter Side 30.0 mm (1.181 in.) 371.44 mm Spark Plug Center Fuel Pump Oil Fill (14.624 in.) Line 85.50 mm (3.366 in.) Dipstick 101.38 mm (3.992 in.) 1/4 in. Square Keyway Keyway 7/16-20 UNF 2B in.
  • Page 11 Specifi cations Engine Dimensions with Low-Profi le Air Cleaner-PTO Side 65.0 mm (2.559 in.) 335.04 mm (13.19 in.) 122.10 mm (4.807 in.) 75.42 mm (2.969 in.) Muffl er Mounting 50.00 mm (1.969 in.) Lift Strap Oil Fill Location 30° Exhaust Port #2 5/16-24 UNC-2B in.
  • Page 12 Specifi cations Engine Dimensions with Low-Profi le Air Cleaner-Starter Side 50.0 mm (1.969 in.) 12.0 mm (0.472 in.) 32.0 mm (1.260 in.) Center Line Spark Dipstick Exhaust Port #1 Exhaust Port #2 Plug 67.50 mm (2.657 in.) 432.58 mm Engine Mounting Center Line Mounting Muffl...
  • Page 13 Lubricate threads with engine oil prior to assembly. Any and all horsepower (hp) references by Kohler are Certifi ed Power Ratings and per SAE J1940 & J1995 hp standards. Details on Certifi ed Power Ratings can be found at KohlerEngines.com.
  • Page 14 Specifi cations TORQUE SPECIFICATIONS ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 Crankcase Breather Cover Fastener 11.3 N·m (100 in. lb.) into new holes 7.3 N·m (65 in. lb.) 7.3 N·m (65 in. lb.) into used holes Oil Temperature Sensor (into breather 7.3 N·m (65 in. lb.) cover) Oil Sentry (into breather cover)
  • Page 15 Specifi cations TORQUE SPECIFICATIONS ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 Ignition (continued) Crankshaft Position Sensor Earlier Design Bracket Crankshaft Position Sensor to Bracket Screw 11.3 N·m (100 in. lb.) Crankshaft Position Sensor Bracket to Crankcase Screw 8.3 N·m (73 in. lb.) Crankshaft Position Sensor Later Design Bracket Crankshaft Position Sensor to Bracket...
  • Page 16 Specifi cations TORQUE SPECIFICATIONS ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 Starter Assembly Thru Bolt 5.6-9.0 N·m (49-79 in. lb.) Nippondenso (Solenoid Shift) 4.5-7.5 N·m (40-84 in. lb.) Delco-Remy (Solenoid Shift) 5.6-9.0 N·m (49-79 in. lb.) Mounting Screw 16.0 N·m (142 in. lb.) 15.3 N·m (135 in.
  • Page 17 Specifi cations CLEARANCE ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 SPECIFICATIONS Connecting Rod (continued) Connecting Rod-to-Piston Pin Running Clearance @ 21°C 0.015/0.028 mm (0.0006/0.0011 in.) 0.015/0.028 mm (0.0006/0.0011 in.) (70°F) Piston Pin End I.D. @ 21°C (70°F) 17.015/17.023 mm (0.6699/0.6702 in.) 17.015/17.023 mm (0.6699/0.6702 in.) Max.
  • Page 18 Specifi cations CLEARANCE ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 SPECIFICATIONS Cylinder Bore Bore I.D. 80.000/80.025 mm 83.006/83.031 mm 82.988/83.013 mm (3.2672/3.2682 in.) (3.1496/3.2689 in.) (3.2680/3.2689 in.) O.D. - Max. Wear Limit 80.075 mm 83.081 mm (3.2709 83.051 mm (3.2697 in.) (3.1526 in.) in.) Max.
  • Page 19 Specifi cations CLEARANCE ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 SPECIFICATIONS Piston, Piston Rings, and Piston Pin (Style A continued) Top Compression Ring-to- Groove Side Clearance 0.050/0.095 mm (0.0019/0.0037 in.) 0.025/0.048 mm (0.0010/0.0019 in.) Middle Compression Ring-to- Groove Side Clearance 0.030/0.075 mm (0.0012/0.00307 in.) 0.015/0.037 mm (0.0006/0.0015 in.) Oil Control Ring-to-Groove Side Clearance...
  • Page 20 Specifi cations CLEARANCE ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 SPECIFICATIONS Valves and Valve Lifters Hydraulic Lifter to Crankcase 0.011/0.048 mm (0.0004/0.0019 in.) 0.0241/0.0501 mm (0.0009/0.0020 in.) Running Clearance Intake Valve Stem-to-Valve 0.040/0.078 mm (0.0016/0.0031 in.) 0.038/0.076 mm (0.0015/0.0030 in.) Guide Running Clearance Exhaust Valve Stem-to-Valve 0.052/0.090 mm (0.0020/0.0035 in.) 0.050/0.088 mm (0.0020/0.0035 in.)
  • Page 21 Specifi cations GENERAL TORQUE VALUES English Fastener Torque Recommendations for Standard Applications Bolts, Screws, Nuts and Fasteners Assembled Into Cast Iron or Steel Grade 2 or 5 Fasteners Into Aluminum Size Grade 2 Grade 5 Grade 8 Tightening Torque: N·m (in. lb.) ± 20% 8-32 2.3 (20) 2.8 (25)
  • Page 22 Here is a list of tools and their source. SEPARATE TOOL SUPPLIERS Kohler Tools SE Tools Design Technology Inc. Contact your local Kohler source of 415 Howard St. 768 Burr Oak Drive supply. Lapeer, MI 48446 Westmont, IL 60559...
  • Page 23 For reaming worn valve guides to accept replacement oversize valves. Can be used in low-speed drill press or with handle below for hand reaming. Reamer Handle Design Technology Inc. For hand reaming using Kohler 25 455 12-S reamer. DTI-K830 AIDS Description Source/Part No.
  • Page 24 Tools and Aids FLYWHEEL HOLDING TOOL ROCKER ARM/CRANKSHAFT TOOL A fl ywheel holding tool can be made out of an old junk A spanner wrench to lift rocker arms or turn crankshaft fl ywheel ring gear and used in place of a strap wrench. may be made out of an old junk connecting rod.

  • Page 25: Troubleshooting

    Troubleshooting TROUBLESHOOTING GUIDE When troubles occur, be sure to check simple causes which, at fi rst, 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 and vary by engine specifi cation. Use these to locate causing factors.
  • Page 26 Troubleshooting EXTERNAL ENGINE INSPECTION Engine Loses Power NOTE: It is good practice to drain oil at a location away ● Dirty air cleaner element. from workbench. Be sure to allow ample time for ● Engine overheated. complete drainage. ● Excessive engine load. ●...
  • Page 27 Troubleshooting CRANKCASE VACUUM TEST WARNING WARNING Carbon Monoxide can cause severe nausea, Rotating Parts can cause severe injury. fainting or death. Stay away while engine is in operation. Avoid inhaling exhaust fumes. Engine exhaust gases contain poisonous carbon Keep hands, feet, hair, and clothing away from all monoxide.
  • Page 28 Troubleshooting COMPRESSION TEST For Command Twins: A compression test is best performed on a warm engine. Clean any dirt or debris away from base of spark plug(s) before removing them. Be sure choke is off, and throttle is wide open during test. Compression should be at least 160 psi and should not vary more than 15% between cylinders.
  • Page 29 Air Cleaner/Intake AIR CLEANER NOTE: Operating engine with loose or damaged air cleaner components could cause premature These systems are CARB/EPA certifi ed and components wear and failure. Replace all bent or damaged should not be altered or modifi ed in any way. components.
  • Page 30 These adaptive values are maintained as FUEL LINE long as ECU is not reset. Low permeation fuel line must be installed on all Kohler During certain operating periods such as cold starts, Co. engines to maintain EPA and CARB regulatory warm up, acceleration, high load, etc., a richer air/fuel...
  • Page 31 EFI SYSTEM-ECH ECU compares input signals to programmed maps in Crankshaft Position Sensor Bracket its memory to determine appropriate fuel and spark requirements for immediate operating conditions. ECU then sends output signals to set injector duration and ignition timing. ECU continually performs a diagnostic check of itself, each of sensors, and system performance.
  • Page 32 EFI SYSTEM-ECH Earlier engines have a separate intake air temperature Fuel injectors mount into intake manifold, and high (IAT) sensor (located in throttle body) and a manifold pressure fuel line attaches to them at top end. absolute pressure (MAP) sensor. Later engines have Replaceable O-rings on both ends of injector prevent a combined temperature/manifold absolute pressure external fuel leakage and also insulate it from heat and...
  • Page 33 EFI SYSTEM-ECH When key switch is turned ON and all safety switch For starting and warm up, ECU will adjust fuel and requirements are met, ECU activates fuel pump module ignition timing, based upon ambient temperature, engine for about six seconds, which pressurizes system for temperature, and loads present.
  • Page 34 EFI SYSTEM-ECH ELECTRICAL COMPONENTS Grey Connector Side Electronic Control Unit (ECU) Pin # Description Pinout of ECU Not Used Black Connector Side Not Used Pin # Function Malfunction Indicator Light (MIL) Ground Ignition Coil #1 Ground Not Used Battery Ground Not Used Diagnostic Communication Line Not Used...
  • Page 35 ECU Reset Procedure 1. Turn key/ignition OFF. 2. Install Red wire jumper from Kohler EFI service kit on to service port (connect white wire to black wire in 4 way diagnostic port). 3. Turn key/ignition ON, then OFF and count 10 seconds.
  • Page 36 EFI SYSTEM-ECH KohlerEngines.com 24 690 01 Rev. K...
  • Page 37 EFI SYSTEM-ECH 24 690 01 Rev. K KohlerEngines.com...
  • Page 38 EFI SYSTEM-ECH KohlerEngines.com 24 690 01 Rev. K...
  • Page 39 EFI SYSTEM-ECH 24 690 01 Rev. K KohlerEngines.com...
  • Page 40 EFI SYSTEM-ECH Contacting (Brush) Type TPS Crankshaft Position Sensor Resistance Table Throttle Between Resistance Continuity Position Terminal Value (Ω) Closed A & C 1400-1800 Full with A & C 3200-4100 Stop Pin Full without A & C 4600-5200 Stop Pin A &...
  • Page 41 EFI SYSTEM-ECH 7. Remove two mounting screws from TPS. Save Replace Magnet Assembly screws for reuse. Remove and discard faulty TPS. Install replacement TPS and secure with original mounting screws. a. Reconnect Black and TPS connector plugs. b. Perform TPS Learn Procedure integrating new sensor to ECU.
  • Page 42 EFI SYSTEM-ECH Engine (Oil) Temperature Sensor Manifold Absolute Pressure Sensor (MAP) A sealed, non-serviceable assembly. A faulty sensor A sealed, non-serviceable assembly. A faulty sensor must be replaced. If a blink code indicates a problem must be replaced. If a blink code indicates a problem with temperature sensor, it can be tested as follows: with manifold absolute pressure sensor, it can be tested as follows:...
  • Page 43 EFI SYSTEM-ECH 6. Check circuits (input, ground), from main harness Cutaway Oxygen Sensor Components (O connector to sensor plug for continuity, damage, etc. Connect one ohmmeter lead to Black pin 8 in main harness connector (as in step 4). Connect other lead to terminal #3 in sensor plug.
  • Page 44 EFI SYSTEM-ECH Sensor Signal Observation Removal Inspection NOTE: Do not cut into or pierce sensor or engine NOTE: Apply anti-seize compound only to threads. wiring to make this connection. Sensor Anti-seize compound will affect sensor produces a very small signal. Corrosion or performance if it gets into lower shield of damage to wiring could lead to an incorrect sensor.
  • Page 45 EFI SYSTEM-ECH Troublshooting-Oxygen Sensor (O Condition Possible Cause Conclusion Low voltage output. Shorted sensor or sensor circuit. Replace sensor or repair wiring. Shorted lead wire. Wiring shorted to ground. Contamination of air reference. Remove source of external contamination, protect air reference area.
  • Page 46 EFI SYSTEM-ECH 1. With engine running at idle, listen for a buzzing or Fuel Injectors clicking sound. 2. Disconnect electrical connector from an injector and WARNING listen for a change in idle performance (only running Explosive Fuel can cause fi res and severe on one cylinder) or a change in injector noise or burns.
  • Page 47 NOTE: If ignition coil(s) are disabled and an ignition pump module and insert pressure test jumper (from fault is registered, system will automatically Kohler EFI Service Kit) between high pressure fuel disable corresponding fuel injector drive line and fuel pump module.
  • Page 48 Please note vent hose routing and replicate after service or component replacement to prevent pinching or abrasion of vent hoses. Only Kohler replacement parts can be used because fi tting is specifi c to system and must be maintained. Visit KohlerEngines.com for recommended Kohler replacement parts.
  • Page 49 EFI SYSTEM-ECH Troubleshooting Guide Condition Possible Cause Faulty spark plugs. Fuel pump not running. Fuel pressure low. Insuffi cient fuel delivery. Engine Starts Hard or Fails to Start TPS set incorrect (ECU Reset and TPS Initialization). When Hot. Crankshaft position sensor loose or faulty. TPS faulty.
  • Page 50 EFI SYSTEM-ECH Function Test Fault Codes Example of Diagnostic Display WARNING High Pressure Fluids can puncture skin and cause severe injury or death. One second pause Do not work on fuel system without proper Fault training or safety equipment. Code One second pause Fluid puncture injuries are highly toxic and hazardous.
  • Page 51 EFI SYSTEM-ECH 0230 Fuel Pump Module Circuit Low Voltage or Open 0232 Fuel Pump Module Circuit High Voltage 0336 Crankshaft Position Sensor Noisy Signal 0337 Crankshaft Position Sensor No Signal 0351 Cylinder 1 Ignition Coil Malfunction 0352 Cylinder 2 Ignition Coil Malfunction 0562 System Voltage Low 0563...
  • Page 52 EFI SYSTEM-ECH Code 0107 Code 0113 Component: Manifold Absolute Pressure (MAP or Component: Intake Air Temperature (IAT or TMAP) Sensor TMAP) Sensor Fault: Intake Air Temperature (IAT or TMAP) Fault: MAP or TMAP Circuit Low Voltage or Sensor Circuit High Voltage or Open Open Condition: Shorted connection, faulty sensor, broken...
  • Page 53 EFI SYSTEM-ECH Code 0122 Code 0131 Component: Throttle Position Sensor (TPS) Component: Oxygen Sensor Fault: TPS Circuit Low Voltage or Open Fault: O2S 1 Circuit Low Voltage Condition: Open connection, broken wire or faulty Condition: Open connection, broken wire or faulty sensor.
  • Page 54 EFI SYSTEM-ECH Code 0171 Code 0172 Component: Fuel System Component: Fuel System Fault: Maximum adaptation limit exceeded Fault: Minimum adaptation limit exceeded Condition: Fuel inlet screen/fi lter plugged, low Condition: Too high pressure at high pressure fuel pressure at high pressure fuel line, TPS line, TPS malfunction, shorted malfunction, shorted connection, faulty connection, faulty sensor or fuel pump...
  • Page 55 EFI SYSTEM-ECH Code 0174 Code 0202 Component: Fuel System Component: Fuel Injector Fault: Lean fuel condition Fault: Injector 2 Circuit Malfunction Condition: Fuel inlet screen/fi lter plugged, low Condition: Injector damaged or faulty, shorted or pressure at high pressure fuel line, TPS open connection.
  • Page 56 EFI SYSTEM-ECH Code 0336 Code 0352 Component: Crankshaft Position Sensor Component: Ignition Coil Fault: Crankshaft Position Sensor Noisy Signal Fault: Cylinder 2 Ignition Coil Malfunction Condition: Air gap incorrect, loose sensor, faulty/bad Condition: Broken wire in harness (may not be battery, shorted or faulty connection, visible), shorted connection or faulty faulty sensor or faulty sensor grounding.
  • Page 57 NOTE: MIL is installed by vehicle OEM. Twelve volt (no fuel delivery) supply to bulb will be part of vehicle wire Condition harness. Kohler key switch model will have MIL ● No fuel on engine with 12V supply to bulb. ● Air in high pressure fuel line Conclusion ●...
  • Page 58 EFI SYSTEM-ECH EFI Diagnostic Flow Diagram START OF TEST PROCEED TO START OF TEST FOR RETEST KEY ON MALFUNCTION REFER TO DIAGNOSTIC AID #1 INDICATOR LIGHT SYSTEM POWER REFER TO ARE FAULT CODES DIAGNOSTIC FAULT CODE SUMMARY PRESENT? CLEAR CODES REFER TO DIAGNOSTIC AID #3 DOES ENGINE START? MIL GOES OFF?
  • Page 59 EFI SYSTEM-BOSCH Gasoline is extremely fl ammable and its vapors can WARNING explode if ignited. Store gasoline only in approved Explosive Fuel can cause fi res and severe containers, in well ventilated, unoccupied buildings, away burns. from sparks or fl ames. Spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition.
  • Page 60 80°C (176°F) to properly adapt. These adaptive values are maintained as Low permeation fuel line must be installed on all Kohler long as ECU is not reset. Co. engines to maintain EPA and CARB regulatory compliance.
  • Page 61 EFI SYSTEM-BOSCH ECU requires a minimum of 7.0 volts to operate. Tip of sensor, protruding into exhaust gas, is hollow. Adaptive memory in ECU is operational whenever Outer portion of tip is surrounded by exhaust gas, with required voltage is present, however adapted values inner portion exposed to ambient air.
  • Page 62 EFI SYSTEM-BOSCH A high-voltage, solid-state, battery ignition system is For starting and warm up, ECU will adjust fuel and used with EFI system. ECU controls ignition output and ignition timing, based upon ambient temperature, engine timing through transistorized control of primary current temperature, and loads present.
  • Page 63 EFI SYSTEM-BOSCH 2. For plastic-cased ECU’s below 24 584 28-S, system 3. Make sure engine has resistor type spark plugs. can be primed by manually cycling fuel pump. 4. Disconnect main harness connector from ECU. a. Turn key switch to “ON/RUN” position. Fuel pump 5.
  • Page 64 EFI SYSTEM-BOSCH Throttle Position Sensor (TPS) Throttle Between Resistance Continuity Position Terminals Value (Ω) Closed 2 & 3 800-1200 Closed 1 & 3 1800-3000 Full 2 & 3 1800-3000 Full 1 & 3 800-1200 1 & 2 1600-2500 If resistance values in steps 3, 4, and 5 are within specifi...
  • Page 65 EFI SYSTEM-BOSCH 7. Locate service connector plug in wiring harness. 6. Run engine at full throttle (above 3000 RPM), to warm up engine and initiate O sensor function in “35 Pin” (MA 1.7) Metal-Cased ECU: Connect a “closed-loop” operation. jumper wire from TPS initialization pin #8 (gray wire) to ground pin (black wire), or use jumper 7.
  • Page 66 EFI SYSTEM-BOSCH 5. Unplug sensor connector and check sensor b. If voltage is not in specifi ed range, reconnect resistance separately. Resistance value should oxygen sensor lead. With lead connected, probe again be 2375-2625 . or connect sensor connection with red VOA meter lead.
  • Page 67 EFI SYSTEM-BOSCH 5. With oxygen sensor disconnected and engine not a. Clean connection and check wiring if circuit was running, disconnect main harness connector from not completed. ECU and set meter to Rx1 scale. Check circuit 3. Set meter for DC voltage. Touch red tester lead to continuity as follows.
  • Page 68 EFI SYSTEM-BOSCH 2. Make sure all safety switch requirements are met. Fuel Injector Details Crank engine and check for fl ashing of test light. Repeat test at other connector. a. If fl ashing occurs, use an ohmmeter (Rx1 scale) and check resistance of each injector across two terminals.
  • Page 69 EFI SYSTEM-BOSCH 16. Reverse appropriate procedures to install new Injector Inspection Points injector(s) and reassemble engine. Use new O-Rings any time an injector is removed (new replacement injectors include new O-Rings). Lubricate O-Rings lightly with oil. Torque fuel rail and blower housing mounting screws to 3.9 N·m (35 in.
  • Page 70 EFI SYSTEM-BOSCH 3. Disconnect secondary lead from spark plug. a. If there was no continuity between pump Connect an ohmmeter set on Rx10K scale terminals, replace fuel pump. between spark plug boot terminal and red b. If voltage was below 7, test wiring harness and primary terminal.
  • Page 71 EFI SYSTEM-BOSCH Internal (In-Tank) Regulator- Idle Speed Screw Dampening Spring Remove screws securing retaining ring and Idle Speed Screw Details regulator in base/holder assembly. Grasp and pull regulator out of base/holder. 5. Always use new O-Rings and hose clamps when installing a regulator.
  • Page 72 EFI SYSTEM-BOSCH If governor/throttle components are all intact, but you think there may be a problem with adjustment, follow Procedure A to check setting. If governor lever was loosened or removed, go immediately to Procedure B to perform initial adjustment. A.
  • Page 73 EFI SYSTEM-BOSCH Faulty spark plugs. Fuel pump not running. Fuel pressure low. Insuffi cient fuel delivery. Engine starts hard or fails to start TPS offset incorrect (Initialization). when hot Speed sensor loose or faulty. TPS faulty. Engine temperature sensor faulty. Faulty injectors.
  • Page 74 EFI SYSTEM-BOSCH “35 Pin” (MA 1.7) Metal-Cased ECU Systems Pin # Component Ignition Coil #1 Not used Engine Speed Sensor ECU Production Test Terminal Not Used Not Used Not Used TPS Initialization Terminal Engine Ground O2 Sensor Not Used Throttle Position Sensor Not Used Oil Temperature Sensor Not Used...
  • Page 75 EFI SYSTEM-BOSCH 24 690 01 Rev. K KohlerEngines.com...
  • Page 76 EFI SYSTEM-BOSCH “24 Pin” (MSE 1.0) Plastic-Cased ECU Systems Pin # Component Permanent Battery Voltage Switched Ignition Voltage Safety Switch 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 Oxygen Sensor Input...
  • Page 77 EFI SYSTEM-BOSCH 24 690 01 Rev. K KohlerEngines.com...
  • Page 78 EFI SYSTEM-BOSCH “32 Pin” (MSE 1.1) Plastic-Cased ECU Systems Pin # Component 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 79 EFI SYSTEM-BOSCH 24 690 01 Rev. K KohlerEngines.com...
  • Page 80 EFI SYSTEM-BOSCH Fuel System Fault Codes ECU continuously monitors engine operation against preset performance limits. If operation is outside limits, WARNING: Fuel System Under Pressure! ECU activates MIL and stores a diagnostic code in its Fuel system operates under high pressure. System fault memory.
  • Page 81 EFI SYSTEM-BOSCH Example of Diagnostic Display 1. Diagnostic display initiated through ignition key sequencing. Long Pause Short Pauses Code 32 Long Pause Code 61 Long Pause Light remains on at end of transmission After the problem has been corrected, fault codes may be cleared as follows. 1.
  • Page 82 EFI SYSTEM-BOSCH "32 Pin" OBD2 "35 Pin" "24 Pin" (MSE P-Code Ap- (MA 1.7) (MSE 1.0) Blink 1.1) plicable to: Connection or Failure Description Metal- Plastic- Note Code Plastic- "32 Pin" (MSE Cased Cased Cased 1.1) ECU/Sys- ECU/ ECU/Sys- ECU/ tem Only System System...
  • Page 83 EFI SYSTEM-BOSCH "32 Pin" OBD2 "35 Pin" "24 Pin" (MSE P-Code Ap- (MA 1.7) (MSE 1.0) Blink 1.1) plicable to: Connection or Failure Description Metal- Plastic- Code Plastic- Note "32 Pin" (MSE Cased Cased Cased 1.1) ECU/Sys- ECU/ ECU/Sys- ECU/ tem Only System System...
  • Page 84 EFI SYSTEM-BOSCH Code 22 Code 23 Component: Throttle Position Sensor (TPS) Component: ECU Fault: Unrecognizable signal is being sent from Fault: ECU is unable to recognize or process sensor (too high, too low, inconsistent). signals from its memory. Condition: A “limp-home” operating mode occurs, Condition: Engine will not run.
  • Page 85 EFI SYSTEM-BOSCH Code 31 Code 32 Component: Fuel Mixture or Oxygen Sensor Component: Oxygen Sensor Fault: System too lean. Oxygen sensor not Fault: No change in sensor output signal. sending expected voltage to ECU. Condition: Open loop operation only, may cause Condition: System operates under “open loop”...
  • Page 86 EFI SYSTEM-BOSCH Code 33 Code 34 Component: Oxygen Sensor/Fuel System Component: Oxygen Sensor/Fuel System Components Fault: System too rich. Temporary fuel adaptation control is at upper limit. Fault: Long term fuel adaptation control is at upper or lower limit. Condition: Fuel Supply Related (nothing lean–only rich) Condition:...
  • Page 87 EFI SYSTEM-BOSCH Code 42 Code 43 and 44 "32 Pin" (MSE 1.1) Plastic-Cased ECU only. Component: Engine (Oil) Temperature Sensor Component: TPS “Auto-Learn” initialization function Fault: Not sending proper signal to ECU. failed, throttle angle out of learning range. Condition: Engine may be hard to start because Fault: While performing TPS “Auto-Learn”...
  • Page 88 EFI SYSTEM-BOSCH Code 51 "32 Pin" (MSE 1.1) Plastic-Cased ECU only. Code 52 "32 Pin" (MSE 1.1) Plastic-Cased ECU only. Component: Injector #1 circuit open, shorted to Component: Injector #2 circuit open, shorted to ground, or shorted to battery. ground, or shorted to battery. Fault: Injector #1 is not functioning because Fault:...
  • Page 89 EFI SYSTEM-BOSCH Code 56 "32 Pin" (MSE 1.1) Plastic-Cased ECU only. “32 Pin” (MSE 1.1) Plastic-Cased ECU: Pin circuits 29 and 84. Component: Fuel pump relay circuit open, shorted to ground, or shorted to battery. ● Ignition switch Fault: Fuel pump, ignition coils, and fuel ●...
  • Page 90 EFI SYSTEM-BOSCH ● Code 51-Injector 1, "32 Pin" (MSE 1.1) Plastic- “32 Pin” (MSE 1.1) Plastic-Cased ECU: Circuits Cased ECU only. 28,85, 30, and 87. ● Code 52-Injector 2, "32 Pin" (MSE 1.1) Plastic- ● Relay Cased ECU only. ● ECU grounds ●...
  • Page 91 EFI SYSTEM-BOSCH 24 690 01 Rev. K KohlerEngines.com...

  • Page 92: Lubrication System

    Lubrication System This engine uses a full pressure lubrication system which delivers oil under pressure to crankshaft, camshaft, connecting rod bearing surfaces, and hydraulic valve lifters. A high-effi ciency gerotor oil pump maintains high oil fl ow and oil pressure, even at low speeds and high operating temperatures.
  • Page 93 Lubrication System CHANGE OIL AND FILTER Installation Change oil while engine is warm. 1. Apply pipe sealant with Tefl on (Loctite 592™ ® ® ® 1. Clean area around oil fi ll cap/dipstick and drain plug. Thread Sealant or equivalent) to threads of switch. Remove drain plug and oil fi...

  • Page 94: Electrical System

    Electrical System SPARK PLUGS Inspection Inspect each spark plug as it is removed from cylinder CAUTION head. Deposits on tip are an indication of general Electrical Shock can cause injury. condition of piston rings, valves, and carburetor. Do not touch wires while engine is running. Normal and fouled plugs are shown in following photos: Normal Spark Plug Component and Details...
  • Page 95 Electrical System Carbon Fouled BATTERY A 12-volt battery with 400 cold cranking amps (cca) is generally recommended for starting in all conditions. A smaller capacity battery is often suffi cient if an application is started only in warmer temperatures. Refer to following table for minimum capacities based on anticipated ambient temperatures.
  • Page 96 Electrical System BATTERY CHARGING SYSTEM NOTE: Observe following guidelines to avoid damage to electrical system and components: ● Make sure battery polarity is correct. A negative (-) ground system is used. ● Disconnect rectifi er-regulator plug and/or wiring harness plug before doing any electric welding on equipment powered by engine.
  • Page 97 Electrical System Condition Conclusion 20/25 amp OK (green) light comes on and stays steady. Disconnect tester black lead attached to 1 AC terminal and reconnect it to other AC terminal. Repeat test. If OK (green) light comes on again, part is good and may be used.
  • Page 98 Electrical System FUSES This engine has 3 blade type automotive fuses. Replacement fuses must have same rating as blown fuse. Use fuse chart below to determine correct fuse. Wire Color Fuse Rating 2 Purple Wires 30-amp Fuse 1 Red Wire w/Black Stripe 10-amp Fuse 1 Red Wire w/White Stripe 2 Red Wires...

  • Page 99: Starter System

    Starter System NOTE: Do not crank engine continuously for more than 10 seconds. Allow a 60 second cool down period between starting attempts. Failure to follow these guidelines can burn out starter motor. NOTE: If engine develops suffi cient speed to disengage starter but does not keep running (a false start), engine rotation must be allowed to come to a complete stop before attempting to restart engine.
  • Page 100 Starter System SOLENOID SHIFT ELECTRIC STARTERS Starter Disassembly Solenoid Shift Starter Components NOTE: Do not reuse old retainer. NOTE: Do not soak armature or use solvent when cleaning. Wipe clean using a soft cloth, or use compressed air. 1. Remove nut and disconnect positive (+) brush lead/ bracket from solenoid terminal.
  • Page 101 Mounting screw 4 brushes and springs are serviced as a set. Use a new Kohler brush and spring kit if replacement is necessary. holes in metal clips must be up/out. Slide brush holder assembly down into place around 1.
  • Page 102 Starter System b. Position brushes back in their slots so they are fl ush with I.D. of brush holder assembly. Insert brush installation tool (with extension), or use tube described above from a prior brush installation, through brush holder assembly, so holes in metal mounting clips are up/out. c.
  • Page 103 Disassembly/Inspection and Service WARNING Before working on engine or equipment, disable engine as Accidental Starts can cause severe injury or follows: 1) Disconnect spark plug lead(s). 2) Disconnect death. negative (–) battery cable from battery. Disconnect and ground spark plug lead(s) before servicing.
  • Page 104 Disassembly/Inspection and Service Clean all parts thoroughly as engine is disassembled. Remove Air Cleaner Assembly Only clean parts can be accurately inspected Heavy Duty Air Cleaner and gauged for wear or damage. There are many 1. Remove nuts securing air cleaner assembly to commercially available cleaners that will quickly remove throttle body.
  • Page 105 Disassembly/Inspection and Service External Governor Control (ECH EFI) Speed Control Cable Clamp Throttle Actuator Bracket Screw Lever (bottom) Throttle Control Lever Spring Washer Flat Washer (top) Return Spring Remove External Governor Controls 1. Disconnect governor spring attaching governor lever to throttle actuator lever. 2.
  • Page 106 Disassembly/Inspection and Service Gasoline is extremely fl ammable and its vapors can WARNING explode if ignited. Store gasoline only in approved Explosive Fuel can cause fi res and severe containers, in well ventilated, unoccupied buildings, away burns. from sparks or fl ames. Spilled fuel could ignite if it comes Do not fi...
  • Page 107 Disassembly/Inspection and Service Remove Fuel Pump Module (ECH EFI) Remove Throttle Body (ECH EFI) 1. Remove screws securing fuel pump module. Throttle Body Components 2. Remove inlet fuel line from fuel pump, keeping it attached at fuel pump module. Do not cut Oetiker clamp unless fuel line or fuel pump module are being replaced.
  • Page 108 Disassembly/Inspection and Service External Engine Components Debris Screen Blower Housing Outer Baffl e Breather Cover Oil Temperature Oil Sentry Inner Baffl e Debris Screen Guard Sensor 4. Remove screws securing outer baffl es. Note location Remove Debris Screen Guard of any lifting strap and position of short screws for Remove screws and spacers securing debris screen reassembly.
  • Page 109 Disassembly/Inspection and Service Remove Inner Baffl es and Breather Cover 1. Remove screws securing inner baffl es to crankcase. 2. Remove inner (valley) baffl es. 3. Remove remaining screws from breather cover. 4. Pry under protruding edge of breather cover with a screwdriver to break gasket seal. Do not pry on sealing surfaces as it could cause damage resulting in leaks.
  • Page 110 Disassembly/Inspection and Service Cylinder Head Components Valve Cover Valve Cover Gasket Hex Flange Screw Rocker Arm Pivot Rocker Arm Push Rod Hydraulic Lifter Valve Cap Valve Spring Valve Keeper Valve Spring Valve Seal Retainer Cylinder Head Cylinder Head Valve Dowel Pin Gasket 1.
  • Page 111 Inspection Check base surface of hydraulic lifters for wear or damage. If lifters need to be replaced, apply a liberal coating of Kohler lubricant (see Tools and Aids) to base of each new lifter before it is installed. Bleeding Lifters To prevent a possible bent push rod or broken rocker arm, it is important to bleed any excess oil out of lifters before they are installed.
  • Page 112 Disassembly/Inspection and Service Inspection and Service Valve Details EXHAUST INSERT EXHAUST VALVE INTAKE VALVE INTAKE INSERT Dimension Intake Exhaust Seat Angle 89° 89° Insert O.D. 36.987/37.013 mm (1.4562/1.4572 in.) 32.987/33.013 mm (1.2987/1.2997 in.) Guide Depth 4 mm (0.1575 in.) 4 mm (0.1575 in.) Guide I.D.
  • Page 113 Disassembly/Inspection and Service Valve Seat Inserts Hardened steel alloy intake and exhaust valve seat inserts are press fi tted into cylinder head. Inserts are not replaceable but can be reconditioned if not too badly pitted or distorted. If cracked or badly warped, cylinder head should be replaced.
  • Page 114 When gear is removed from Inspect ring gear for cracks or damage. Kohler does not shaft, these tabs are destroyed and gear must provide ring gear as a serviceable part. Replace fl ywheel be replaced.
  • Page 115 Disassembly/Inspection and Service Oil Pump Assembly (Style A) Oil Pump Assembly (Style B) Oil Pump (Style A) Torque Sequence Oil pump is mounted inside closure plate. If service is required, continue with Disassembly, Inspection, and Reassembly. Disassembly 1. Remove screws. 2.
  • Page 116 Disassembly/Inspection and Service Crankcase Components Closure Plate Gerotor Gears Oil Pump Assembly Closure Plate Seal (Style A) (Style A) (Style A) Governor Shaft Governor Washer Governor Gear Governor Cup Camshaft Connecting Rod Crankshaft Piston (Style B) Piston Pin Retainer Governor Cross Piston Pin Crankcase Clip...
  • Page 117 Disassembly/Inspection and Service Governor Cross Shaft Oil Seal Piston and Rings Cross Shaft Oil Seal Details Inspection Piston and Rings Components and Details Style A Style B Top Compression Piston Ring Middle Compression Rails Ring 2.0 mm (0.0787 in.) Oil Control Ring Expander Governor Cross Shaft Seal (3 Piece)
  • Page 118 Disassembly/Inspection and Service specifi c area of piston. Detonation generally occurs from 80 mm bore engines: Top compression ring end gap using low octane fuels. is 0.100/0.279 mm (0.0039/0.0110 in.). Middle compression ring end gap is 1.400/1.679 mm Preignition or ignition of fuel charge before timed spark (0.0551/0.0661 in.).
  • Page 119 Disassembly/Inspection and Service NOTE: If crankpin is reground, visually check to ensure Connecting Rods fi llet blends smoothly with crankpin surface. Offset, stepped-cap connecting rods are used in all NOTE: To prevent repeat failures, camshaft and these engines. crankshaft should always be replaced as a set. Inspection and Service Inspect gear teeth of crankshaft.
  • Page 120 23°-33° Crosshatch 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 new diameter...
  • Page 121 Disassembly/Inspection and Service Measuring Piston-to-Bore Clearance Piston Detail Style A Style B Model Dimension A Dimension B ECH630-ECH680 6 mm (0.2362 in.) 13 mm (0.5118 in.) ECH730-ECH749 6 mm (0.2362 in.) 6 mm (0.2362 in.) CH26/CH735/ 6 mm (0.2362 in.) 6 mm (0.2362 in.) CH745 NOTE: Do not use a feeler gauge to measure piston-to- bore clearance –...
  • Page 122 Reassembly Crankcase Components Closure Plate Gerotor Gears Oil Pump Assembly Closure Plate Seal (Style A) (Style A) (Style A) Governor Shaft Governor Washer Governor Gear Governor Cup Camshaft Connecting Rod Crankshaft Piston (Style B) Piston Pin Retainer Governor Cross Piston Pin Crankcase Clip Shaft...
  • Page 123 Reassembly NOTE: Proper orientation of piston/connecting rod Install Flywheel End Oil Seal assemblies inside engine is extremely important. Oil Seal Detail Improper orientation can cause extensive wear or damage. Be certain pistons and connecting rods are assembled exactly as shown. NOTE: Align chamfer of connecting rod with chamfer of its mating end cap.
  • Page 124 Reassembly Clearance Specifi cations-Crankshaft End Play Shims Governor Gear Assembly Green 0.8366-0.9127 mm Governor gear assembly is located inside closure plate. (0.8750 mm/0.034 in. Nominal) If service was required, and governor was removed, Yellow 1.0652-1.1414 mm refer to assembly procedures under Governor Gear (1.1033 mm/0.043 in.
  • Page 125 Reassembly Install Closure Plate Assembly Closure Plate Fastener Torque Sequence RTV Must Be All Around O-ring Groove. RTV sealant is used as a gasket between closure plate and crankcase. Refer to Tools and Aids for a listing of approved sealants. Always use fresh sealant. Using Install Stator and Backing Plate outdated sealant can result in leakage.
  • Page 126 Reassembly Install Flywheel CAUTION Using improper procedures can lead to broken fragments. Broken fragments could be thrown from engine. Always Damaging Crankshaft and Flywheel Can observe and use precautions and procedures when cause personal injury. installing fl ywheel. Flywheel Components Flywheel Fan Flywheel Stator...
  • Page 127 Reassembly Install Hydraulic Lifters NOTE: Hydraulic lifters should always be installed in same position as before disassembly. Exhaust lifters are located on output shaft side of engine while intake lifters are located on fan side of engine. Cylinder numbers are embossed on top of crankcase and each cylinder head.
  • Page 128 Reassembly Studs closest to lifters must have an exposed height of Valve Stem Seals 75 mm (2 15/16 in.). These engines use valve stem seals on intake valves Studs furthest from lifters must have an exposed height and on exhaust valves. Always use a new seal whenever of 69 mm (2 3/4 in.).
  • Page 129 Reassembly Intake Manifold Components (ECH EFI) MAP or TMAP Fuel Injector Fuel Rail Metal Retaining Clip Sensor Crankshaft Position Crankshaft Position Intake Manifold Sensor (Earlier Sensor (Later Design Bracket Design Bracket) Install Intake Manifold Install Fuel Injectors NOTE: Ensure all parts are clean, undamaged and free Torque Sequence of debris and make sure electrical connectors have seal in place.
  • Page 130 Reassembly Install Manifold Absolute Pressure (MAP) Sensor or Install Valve Covers Temperature/Manifold Absolute Pressure (TMAP) Torque Sequence Sensor (ECH EFI) NOTE: Ensure all parts are clean, undamaged and free of debris and make sure electrical connector has seal in place. 1.
  • Page 131 Reassembly External Engine Components Debris Screen Blower Housing Outer Baffl e Breather Cover Oil Temperature Oil Sentry Inner Baffl e Debris Screen Guard Sensor 4. Install inner baffl es using remaining screws and Install Breather Cover and Inner Baffl es fi...
  • Page 132 Reassembly 2. Torque black rectifi er-regulator screws to 1.4 N·m Install Blower Housing and Outer Baffl es (12.6 in. lb.). NOTE: Do not completely tighten screws until all items a. Torque silver or green ground strap screw to are installed to allow shifting for hole alignment. 2.8 N·m (25 in.
  • Page 133 Reassembly 2. To assist assembly, fi nd 4 intake manifold studs with 1. Install ECU to ECU bracket using screws. Torque M6 thread at least 100 mm in length to be used as M5 screws to 6.2 N·m (55 in. lb.) into new holes or guide pins.
  • Page 134 Reassembly 6. Connect 5/32" I. D. vent hose from fuel pump module to throttle body. 7. Push electrical connector onto throttle position sensor making sure a good connection is made. Gasoline is extremely fl ammable and its vapors can WARNING explode if ignited.
  • Page 135 Reassembly 1. Install lift fuel pump (pulse or mechanical) and lines as an assembly. Connect pulse line to crankcase vacuum fi tting if engine has a pulse lift fuel pump. 2. Install lift fuel pump to bracket on housing using screws. Torque to M6 screws to 7.3 N·m (68 in. lb.) into new holes or 6.2 N·m (55 in.
  • Page 136 Reassembly WARNING Before working on engine or equipment, disable engine as Accidental Starts can cause severe injury or follows: 1) Disconnect spark plug lead(s). 2) Disconnect death. negative (–) battery cable from battery. Disconnect and ground spark plug lead(s) before servicing. External Engine Components Heavy-Duty Air Low-Profi...
  • Page 137 Reassembly Install Throttle Control Panel Install Oil Cooler (if equipped) NOTE: To identify various parts and assembly of throttle 1. Secure adapter to closure plate with oil fi lter nipple. control panel, refer to External Governor Control Torque oil fi lter nipple to 28.5 N·m (21 ft. lb.). Components.
  • Page 138 Reassembly Sensitivity Adjustment Governor Lever Hole 1 Hole 2 Hole 3 Hole 4 Governor sensitivity is adjusted by repositioning governor spring in holes of governor lever. If speed surging occurs with a change in engine load, governor is set too sensitive. If a big drop in speed occurs when normal load is applied, governor should be set for greater sensitivity.
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This manual is also suitable for:

Command pro ch745Command pro ch735Command pro ch26Command pro ech630

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