Harbor Freight Tools 179cc Owner's Manual & Safety Instructions page 17

Problem
Engine misfires 1. Spark plug cap loose.
2. Incorrect spark plug gap or
damaged spark plug.
3. Defective spark plug cap.
4. Old or low quality gasoline.
5. Incorrect compression.
Engine stops 1. Low oil shutdown.
suddenly
2. Fuel tank empty or full of impure or low
quality gasoline.
3. Defective fuel tank cap creating
vacuum, preventing proper fuel flow.
4. Faulty magneto.
5. Disconnected or improperly
connected spark plug cap.
Engine knocks 1. Old or low quality gasoline.
2. Engine overloaded.
3. Incorrect spark timing, deposit
buildup, worn engine, or other
mechanical problems.
Engine backfires 1. Impure or low quality gasoline.
2. Engine too cold.
3. Intake valve stuck or overheated engine.
4. Incorrect timing.
Equipment does 1. Engine idling.
not operate with
engine running
2. Broken or loose belt.
Follow all safety precautions whenever diagnosing or servicing the equipment or engine.
Item 69086
Possible Causes
For engine technical questions, please call 1-800-520-0882.
For other technical questions, please call 1-800-444-3353.
Probable Solutions
1. Check wire connections.
2. Re‑gap or replace spark plug.
3. Replace spark plug cap.
4. Use only fresh 87+ octane
unleaded gasoline.
Do not use gasoline with more than
10% ethanol (E15, E20, E85, etc.).
5. Diagnose and repair compression.
(Use Engine will not start:
COMPRESSION RELATED section.)
1. Fill engine oil to proper level. Check
engine oil before EVERY use.
2. Fill fuel tank with fresh 87+ octane
unleaded gasoline.
Do not use gasoline with more than
10% ethanol (E15, E20, E85, etc.).
3. Test/replace fuel tank cap.
4. Have qualified technician service magneto.
5. Secure spark plug cap.
1. Fill fuel tank with fresh 87+ octane
unleaded gasoline.
Do not use gasoline with more than
10% ethanol (E15, E20, E85, etc.).
2. Do not exceed equipment's load rating.
3. Have qualified technician
diagnose and service engine.
1. Fill fuel tank with fresh 87+ octane
unleaded gasoline.
Do not use gasoline with more than
10% ethanol (E15, E20, E85, etc.).
2. Use cold weather fuel and oil
additives to prevent backfiring.
3. Have qualified technician
diagnose and service engine.
4. Check engine timing.
1. This is normal operation.
Increase engine speed to start operation.
2. Inspect belt and replace if broken or worn.
Tension belt properly.
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