Problem Cause Solution
Engine stops
when under
heavy load
Dirty air filter Clean or replace element.
Engine running cold. Allow engine to warm up prior to
operating equipment.
Engine knocks Old or low quality gasoline. Fill fuel tank with fresh 87+ octane
unleaded gasoline.
Engine overloaded. Do not exceed equipment’s load rating.
Incorrect spark timing, deposit
buildup, worn engine, or other
mechanical problems.
Have qualified technician diagnose and
service engine.
Engine backfire
s
Impure or low quality gasoline. Fill fuel tank with fresh 87+ octane
unleaded gasoline.
Engine too cold. Use cold weather fuel and oil additives to
prevent backfiring.
Intake valve stuck or
overheated engine.
Have qualified technician diagnose and
service engine.
Incorrect timing. Check engine timing.
Follow all safety precautions whenever diagnosing or servicing the equipment
or engine.
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