Kohler CH25S Troubleshooting
| Engine Model: Kohler Command CH25S |
| Engine Type: 4-cycle V-Twin cylinder horizontal shaft air-cooled gasoline |
| Total Displacement: 44 cu.in (725 cc) |
| Rated Engine Power: 25 Hp (18.5 kW) at 3600 rpm |
| Carburetor Type: One-barrel with fixed main jet |
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| Engine won't start or hard to start |
No fuel in fuel tank - Add fuel.
Incorrect fuel grade - Use correct fuel grade.
Dirt and debris in fuel system - Remove debris and dirt.
Spark plug wire is disconnected or loose - Inspect spark plug wiring connection, change or repair.
Spark plug is faulty - Replace spark plug.
Fuel filter is dirty - Replace fuel filter.
Brake pedal not depressed - Press the brake pedal.
Carburetor is not working properly - Inspect and adjust.
Low cylinder compression - Check cylinder block and replace worn parts.
Unadjusted or worn throttle cable - Adjust correctly or change the cable.
Cooling fins are plugged - Need to wash or clean.
Defective ignition - Inspect ignition system and change failed components.
Throttle cable is stuck or faulty - Replace or clean the cable.
Clogged air filter - Replace or service air filter.
Fuel pump is faulty or clogged - Clean or install new fuel pump.
| Engine starts and stalls immediately |
Spark plug is damaged - Change spark plug.
Clogged or faulty carburetor - Service or replace carburetor.
Ignition coil is damaged - Change ignition coil as required.
Bad or damaged valve springs - Replace valve springs.
Stuck valves - Valves need to be cleaned.
Engine oil level low - Check and refill engine oil.
Engine is under excessive load - Reduce load.
Air intake screen is blocked - Wash or clean as required.
Too lean fuel mixture in carburetor - Set the carburetor correctly.
Incorrect ignition timing - Ignition timing needs to be set properly.
Valve setting is incorrect - Set the valves properly.
| Abnormal engine noise or knocking |
Low octane fuel - Use proper gasoline.
Excessive engine load - Reduce the load.
Lack of engine oil - Need to add engine oil.
Low idle speed setting is incorrect - Adjustment required.
Clogged or damaged fuel pump - Clean or change fuel pump.
Crankshaft or main bearings failure - Need to install new components.
Improper valve clearance - Need to adjust valve clearance.
Piston rings or cylinder bore are worn - Change defective parts.
Carburetor is clogged or improperly adjusted - Adjust carburetor properly or service it.
Clogged air filter - Service or replace air filter.
Fuel pump is faulty or clogged - Check fuel pump and change if required.
Defective ignition - Inspect ignition system and change failed components.
Damaged cylinder-head gasket - Replace the head gasket.
Valves are burned or stuck - Replace or service valves.
Push rod is bent or worn - Install a new push rod.
Worn cylinder block parts - Defective components need to be replaced.
Oil filter is dirty (if equipped) - Service or change oil filter.
| Engine uses too much fuel |
Insufficient choke opening - Inspect choke cable and adjust as required.
Improper adjustment of carburetor main jet - Adjust it properly.
Spark plug is loose or defective - Re-tighten or replace spark plug.
Worn, stuck, or burned valves - Replace or clean valves.
Rings, sleeve, or piston are damaged - Change defective parts.
Valve clearance is incorrect - Adjustment procedure required.
| Engine oil consumption is too high |
Worn gaskets or seals - To repair leaks, replace worn parts.
Damaged valve guides or valve stems - Valves need to be changed.
Damaged or seized piston rings - Change the piston rings as required.
Cylinder liner or piston is damaged - Inspect liner and piston, change as necessary.
Clogged breather hose or pipe - Change or service.
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