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Kohler CH11S Troubleshooting

Engine Model: Kohler Command CH11S
Engine Type: 4-cycle 1-cylinder air-cooled gasoline engine
Total Displacement: 24.3 (398 cc)
Rated Engine Power: 11.0 Hp (8.2 kW) at 3600 rpm
Carburetor Type: Adjustable or fixed main jet


Engine won't start or starts hard

Empty gas tank - Fill it up.
Low-quality gasoline - Use quality fuel.
Clogged fuel system - Remove clogging.
Spark plug wiring connection is defective - Check the spark plug wire connection, repair or replace.
Defective spark plug - Change spark plug as required.
Plugged fuel filter - Fuel filter needs changing.
Safety contact for brake pedal defective - Install new part.
Problems with carburetor adjustment - Adjust as required.
Engine has bad compression - Check cylinder block and change wear parts.
Throttle cable is worn or adjusted improperly - Adjust properly or replace the cable.

Irregular engine running

Clogged cooling fins - Clean and wash as required.
Defective ignition - Check ignition and replace faulty components.
Throttle cable is faulty or stuck - Change or clean the cable.
Clogged air filter - Replace or clean air filter.
Dirty or faulty fuel pump - Service or replace fuel pump.

Engine starts but then stalls

Faulty spark plug - Spark plug need to be replaced.
Carburetor is defective or clogged - Clean or change carburetor.
Ignition coil is faulty - Ignition coil should be replaced.
Loose or broken valve springs - Valve springs need to be changed.
Stuck valves - Clean the valves.

Engine overheated

Engine oil level low - Fill up the engine oil.
Engine is overloaded - Reduce the load.
Cooling fins are plugged - Clean and wash as required.
Too lean fuel mixture in carburetor - Adjust carburetor properly.
Bad ignition timing - Adjust ignition timing as required.
Wrong valve setting - Valves needs to be adjusted properly.

Engine knocking or noise

Stale gasoline - Use proper fuel.
Engine is overloaded - Load reducing is recommended.
Engine oil insufficient - Check oil level and add oil as required.
Incorrectly adjusted low idle speed - Adjust idle speed.
Dirty or faulty fuel pump - Clean or change fuel pump.
Worn crankshaft or main bearings - Crankshaft or bearings need to be replaced.
Valve clearance is improper - Adjust valve clearance.
Damaged cylinder bore or piston rings - Replace defective parts.

Engine loses power

Carburetor is clogged or improperly adjusted - Adjust carburetor properly or service it.
Air filter element is plugged - Replace or service air filter.
Clogged or defective fuel pump - Service or replace fuel pump.
Ignition system is defective - Inspect ignition system and change failed components.
Defective cylinder head gasket - Install new cylinder head gasket.
Stuck or burned valves - Replace or service valves.
Push rod is damaged or worn - Push rod needs to be changed.
Damaged cylinder block components - Defective parts need to be replaced.
Oil filter element is plugged (if equipped) - Clean or change oil filter.

High fuel consumption

Throttle did not open fully - Replace or adjust throttle cable.
Carburetor main jet is improperly adjusted - Adjust the carburetor main jet correctly.
Faulty or loose spark plug - Spark plug need to be tightened or replaced.
Valves are stuck, worn, or burned - Change or service valves.
Worn sleeve, rings, or piston - Change faulty components.
Improper valve clearance - Adjust valve clearance according to specifications.

Engine using too much oil

Damaged seals or gaskets - Replace worn parts to avoid leaks.
Worn valve guides and valve stems - Change the valves.
Damaged or seized piston rings - Have piston rings replaced.
Damaged cylinder liner or piston - Inspect liner and piston, replace as necessary.
Blocked breather hose or pipe - Replace or clean.