CH18-CH25, CH620-CH730, CH740, CH750 ... - Kohler Engines

1 CH18-CH25, CH620-CH730, CH740, CH750 . 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 Specifications 14 Tools and Aids 17 Troubleshooting 21 Air Cleaner/Intake 22 Fuel System 28 Governor System 30 Lubrication System 32 Electrical System 48 Starter System 57 Clutch 59 Disassembly/Inspection and Service 72 Reassembly 24 690 06 Rev. C 1. 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. WARNING WARNING CAUTION. Explosive Fuel can cause Accidental Starts can Electrical Shock can fires and severe burns.

2 Cause severe injury or cause injury. Do not fill fuel tank while death. Do not touch wires while engine is hot or running. Disconnect and ground engine is running. Gasoline is extremely flammable spark plug lead(s) before and its vapors can explode if servicing. CAUTION. ignited. Store gasoline only in approved containers, in well Before working on engine or Damaging Crankshaft ventilated, unoccupied buildings, equipment, disable engine as and Flywheel can cause away from sparks or flames. follows: 1) Disconnect spark plug personal injury. Spilled fuel could ignite if it comes lead(s). 2) Disconnect negative ( ). in contact with hot parts or sparks battery cable from battery. from ignition. Never use gasoline as a cleaning agent. WARNING Using improper procedures can Hot Parts can cause lead to broken fragments. Broken WARNING severe burns. fragments could be thrown from engine . Always observe and use Rotating Parts can cause Do not touch engine precautions and procedures when severe injury.

3 While operating or just installing flywheel. Stay away while engine after stopping. is in operation. Never operate engine with heat CAUTION. Keep hands, feet, hair, and shields or guards removed. clothing away from all moving Failure to utilize or parts to prevent injury. Never reassemble debris WARNING screen as designed could operate engine with covers, shrouds, or guards removed. Cleaning Solvents can result in debris screen cause severe injury or failure and serious death. personal injury. WARNING. Use only in well Carbon Monoxide can ventilated areas away WARNING. cause severe nausea, from ignition sources. fainting or death. Uncoiling Spring can Carburetor cleaners and solvents cause severe injury. Avoid inhaling exhaust are extremely flammable. Follow fumes. cleaner manufacturer's warnings Wear safety goggles or and instructions on its proper and face protection when engine exhaust gases contain servicing retractable poisonous carbon monoxide.

4 Safe use. Never use gasoline as a cleaning agent. starter. Carbon monoxide is odorless, colorless, and can cause death if Retractable starters contain a inhaled. powerful, recoil spring that is under tension. Always wear safety goggles when servicing retractable starters and carefully follow instructions in Retractable Starter for relieving spring tension. 2 24 690 06 Rev. C. Maintenance MAINTENANCE INSTRUCTIONS. WARNING. Accidental Starts can cause severe injury or Before working on engine or equipment, disable engine as death. follows: 1) Disconnect spark plug lead(s). 2) Disconnect Disconnect and ground spark plug lead(s) negative ( ) battery cable from battery. before servicing. Normal maintenance, replacement or repair of emission control devices and systems may be performed by any repair establishment or individual; however, warranty repairs must be performed by a Kohler authorized dealer. MAINTENANCE SCHEDULE.

5 Weekly Check heavy-duty air cleaner element. Air Cleaner/Intake Every 25 Hours or Annually . Service/replace low-profile precleaner. Air Cleaner/Intake Every 100 Hours or Annually . Replace low-profile air cleaner element. Air Cleaner/Intake Change oil. Lubrication System/Clutch Remove cooling shrouds and clean cooling areas. Air Cleaner/Intake Check oil cooler fins, clean as necessary (if equipped). Lubrication System Every 200 Hours Change oil filter. Lubrication System Replace fuel filter. Every 250 Hours . Replace heavy-duty air cleaner element and check inner element. Air Cleaner/Intake Every 500 Hours . Replace heavy-duty inner air cleaner element. Air Cleaner/Intake Replace spark plugs and set gap. Electrical System Every 500 Hours2. Have crankshaft spline lubricated. 1. Perform these procedures more frequently under severe, dusty, dirty conditions. 2. Have a Kohler authorized dealer perform this service.

6 REPAIRS/SERVICE PARTS. Kohler genuine service parts can be purchased from Kohler authorized dealers. To find a local Kohler authorized dealer visit or call 1-800-544-2444 ( and Canada). 24 690 06 Rev. C 3. Maintenance OIL RECOMMENDATIONS STORAGE. We recommend use of Kohler oils for best performance. If engine will be out of service for 2 months or more Other high-quality detergent oils (including synthetic) follow procedure below. of API (American Petroleum Institute) service class SJ 1. Add Kohler PRO Series fuel treatment or equivalent or higher are acceptable. Select viscosity based on to fuel tank. Run engine 2-3 minutes to get stabilized air temperature at time of operation as shown in table fuel into fuel system (failures due to untreated fuel below. are not warrantable). 2. Change oil while engine is still warm from operation. Remove spark plug(s) and pour about 1 oz. of engine oil into cylinder(s).

7 Replace spark plug(s) and crank engine slowly to distribute oil. 3. Disconnect negative (-) battery cable. 4. Store engine in a clean, dry place. FUEL RECOMMENDATIONS. WARNING. Explosive Fuel can cause fires and severe burns. Do not fill fuel tank while engine is hot or running. 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. Spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition. Never use gasoline as a cleaning agent. NOTE: E15, E20 and E85 are NOT approved and should NOT be used; effects of old, stale or contaminated fuel are not warrantable. Fuel must meet these requirements: Clean, fresh, unleaded gasoline. Octane rating of 87 (R+M)/2 or higher. Research Octane Number (RON) 90 octane minimum. Gasoline up to 10% ethyl alcohol, 90% unleaded is acceptable.

8 Methyl Tertiary Butyl Ether (MTBE) and unleaded gasoline blend (max 15% MTBE by volume) are approved. Do not add oil to gasoline. Do not overfill fuel tank. Do not use gasoline older than 30 days. 4 24 690 06 Rev. C. Specifications engine Dimensions with Low-Profile Air Cleaner Dimensions in millimeters. Inch equivalents shown in [ ]. 24 690 06 Rev. C 5. Specifications engine Dimensions with Heavy-Duty Air Cleaner Dimensions in millimeters. Inch equivalents shown in [ ]. [ ] [ ] [ ] [ ] [ ] AIR FILTER RAIN AIR FILTER COVER [ ]. CAP REMOVAL [ ] [ ] ASSEMBLY REMOVAL. LIFT STRAP. OIL FILL [ ]. LOCATION SAFETY AIR FILTER. ELEMENT REMOVAL. PULSE [ ]. FUEL PUMP PRIMARY AIR FILTER. ELEMENT REMOVAL. 30 30 . [.613]. SPARK PLUG. CRANKSHAFT. [ ]. SOLENOID. SHIFT STARTER 3/8-16 UNC 2B (INCH). [.669]. [ ] 7/16-14 UNC 2B (INCH). [.618] [.827]. OIL FILTER [ ] REMOVAL engine MOUNTING SURFACE. [ ] engine CRANKSHAFT. [ ].

9 MOUNTING [ ]. HOLE A . [ ]. [ ] [ ]. LIFT STRAP. OIL DIPSTICK. [ ]. 1/4 IN. SQ KEYWAY. [ ] 1/4 IN. SQ KEYWAY. [ ]. [ ]. 7/16-20 UNF 2B (INCH). ( ). 3/8-16 UNC 2B. [.750]. [ ]. [ ]. 2X OIL DRAIN PLUG [ ] engine . [ ] MOUNTING HOLE A [ ] MOUNTING. 3/8 NPT (INCH). SURFACE. 6 24 690 06 Rev. C. Specifications engine IDENTIFICATION NUMBERS. Kohler engine identification numbers (model, specification and serial) should be referenced for efficient repair, ordering correct parts, and engine replacement. Model .. CH620. Command engine Horizontal Shaft Numerical Designation Specification .. CH620-0001. Serial .. 3923500328. Year Manufactured Code Factory Code Code Year 39 2009. 40 2010. 41 2011. GENERAL SPECIFICATIONS3,6 CH18/CH20/ CH22/CH23/ CH25/ CH750 . CH22/ CH670-CH680 CH730/CH740. CH620-CH640. Bore 77 mm 80 mm 83 mm ( in.). ( in.) ( in.). Stroke 67 mm ( in.) 69 mm ( in.). Displacement 624 cc 674 cc 725 cc 747 cc (38 cu.)

10 In.) (41 cu. in.) (44 cu. in.) (46 cu. in.). Oil Capacity (refill) L ( qt.). Maximum Angle of Operation (@ full oil level)4 25 . TORQUE SPECIFICATIONS3,5 CH18/CH20/ CH22/CH23/ CH25/ CH750 . CH22/ CH670-CH680 CH730/CH740. CH620-CH640. Blower Housing and Sheet Metal M5 Fasteners N m (55 in. lb.) into new holes N m (35 in. lb.) into used holes M6 Fasteners N m (95 in. lb.) into new holes N m (65 in. lb.) into used holes Carburetor and Intake Manifold Intake Manifold Mounting Fastener (torque in 2 first to N m (66 in. lb.). increments) finally to N m (88 in. lb.). M6 Mounting Screw N m (55-65 in. lb.). Adapter (for Heavy-Duty Air Cleaner) Mounting N m (65 in. lb.). Fastener Closure Plate Fastener N m (216 in. lb.). 3. Values are in Metric units. Values in parentheses are English equivalents. 4. Exceeding maximum angle of operation may cause engine damage from insufficient lubrication. 5. Lubricate threads with engine oil prior to assembly.