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Kohler M18 Troubleshooting

Engine Model: Kohler Magnum M18
Engine Type: 4-cycle twin-cylinder air-cooled gasoline engine
Total Displacement: 42.2 (691.3 cc)
Rated Engine Power: 18.0 Hp (13.4 kW) at 3600 rpm
Carburetor Type: Adjustable or fixed main jet


Engine starts hard or doesn't start

Fuel tank is empty - Fill gasoline up.
Improper fuel grade - Change gasoline.
Dirt and debris in fuel system - Remove debris and dirt.
Defective wiring connection of spark plug - Check spark plug wiring connection, repair or change.
Spark plug is damaged - Install new spark plug.
Fuel filter is clogged - Fuel filter needs to be replaced.
Brake pedal not pushed down - Push the brake pedal down.
Carburetor is clogged - Clean the carburetor.
Poor engine compression - Check cylinder block and replace damaged components.
Worn or improperly adjusted choke cable - Replace cable or adjust properly.

Irregular engine running

Cooling fins are plugged - Wash or clean as required.
Ignition system failure - Check ignition and replace faulty components.
Throttle cable is stuck or defective - Service or replace the cable.
Air filter element is clogged - Clean or replace air filter.
Fuel pump is faulty or clogged - Check fuel pump and replace if necessary.

Engine starts but immediately shuts off

Faulty spark plug - Install new spark plug.
Carburetor is faulty or clogged - Replace or service carburetor.
Damaged ignition coil - Change ignition coil as required.
Valve springs are damaged or weak - Replace valve springs.
Valves are stuck - Valves need to be cleaned.

Engine overheats

Engine oil level is low - Check oil level and add oil as required.
Engine overload - Load reducing is recommended.
Cooling fins are clogged - Need to wash or clean.
Carburetor mixture is too lean - Set the carburetor correctly.
Ignition timing is incorrect - Adjust ignition timing correctly.
Valve setting is incorrect - Set the valves correctly.

Engine knocks or noises

Low octane gasoline - Use correct gasoline.
Engine overloaded - Load reducing required.
Low engine oil level - Fill up the engine oil.
Wrong adjustment of low idle speed - Adjust as required.
Fuel pump is faulty or clogged - Clean or install new fuel pump.
Crankshaft or main bearings are worn out - Repair or replace defective parts.
Valve clearance is not correct - Adjustment procedure required.
Damaged piston rings or cylinder bore - Change faulty parts.

Engine power loss

Incorrectly adjusted or clogged carburetor - Adjust the carburetor properly or clean it.
Air filter is dirty - Service or replace air filter.
Dirty or damaged fuel pump - Inspect fuel pump and change as required.
Ignition failure - Inspect ignition system and change failed components.
Cylinder head gasket is blown - Install new cylinder head gasket.
Valves are burned or stuck - Clean or replace valves.
Bent or worn push rod - Install a new push rod.
Worn cylinder block parts - Replace defective parts.
Oil filter element is clogged (if equipped) - Change or clean oil filter.

Engine uses too much fuel

Throttle does not open well - Inspect throttle cable and adjust it.
Carburetor main jet adjustment is incorrect - Adjust it properly.
Spark plug is loose or defective - Re-tighten or change the spark plug.
Worn, stuck, or burned valves - Clean or change valves.
Worn rings, piston, or sleeve - Replace faulty components as required.
Excessive valve clearance - Check and adjust.

Engine consuming too much oil

Gaskets or seals can be faulty - To repair leaks, replace worn parts.
Valve stems or guides are damaged - Need to replace the valves.
Piston rings are seized or worn - Have piston rings replaced.
Scored piston or cylinder liner - Inspect piston and liner, replace as required.
Plugged breather hose or pipe - Change or service.