Engine will not start - no spark

Dry, clean, replace, or adjust gap of spark plug to 0.7 mm (0.28 in.).

Defective ignition module.

Engine will not start - has spark

Engine flooded - remove spark plug and pull starter rope 5-20 times.

Improper fuel mixture - replace with John Deere Premium Exact Mix (50:1).

Worn cylinder, piston and piston ring.

Loose spark plug.

Empty fuel tank.

Loose fuel line fitting or carburetor.

Clogged fuel filter.

Clogged air vent in fuel tank.

Insufficient Power

Clogged air filter.

Clogged muffler.

Clogged fuel passage.

Water in fuel.

Engine Overheating

Dirty carburetor.

Improper mixed oil.

Dirty fan cover, cylinder fins.

Forced operation.

Engine Knocks

Overheating cylinder.

Improper fuel.

Carbon deposits in combustion chamber.

Air Suction

Loose carburetor.

Loose fuel line.

Engine Stops While In Operation

Defective stop button.

Plug cap dislocated.

Worn piston.

Carbon deposit on spark plug.

Defective ignition module.

Empty fuel tank.

Clogged carburetor.

Clogged fuel tank.

Water in fuel.

Engine Will Not Stop When Turned Off

Defective stop button.

End of spark plug red heated.

Shaft Vibrates

Unequal string length.

String is worn out.

Saw or brush blade not centered on flange.

Grease or oil in clutch housing.

Lower gear case out of grease.