Why generators show "light pounding knock": 18 documented causes and brand-specific fixes, compiled across 10 manufacturers.
Loose connecting rod bearing.
2 brands- Cummins/Onan: Adjust or replace.; Adjust or replace. Low oil supply. Add oil. Oil badly diluted. Change oil.
- Doosan: Adjust or replace. Low oil supply. Add oil. Oil badly diluted. Change oil.
Loose connecting rod. Low oil supply. Oil badly diluted.
2 brands- Cummins/Onan: Adjust clearance or replace. Add oil. Change if necessary.
- D.W.Onan: Adjust clearance or replace. Add oil. Change if necessary.
Loose connecting rod. Low oil supply, Oil badly diluted. Low oil pressure.
2 brands- Cummins/Onan: Replace rod bearings. Add oil. Change if necessary. Drain. Refill with proper oil. See Low Oil Pressure for remedies.
- Onan Electric: Replace rod bearings. Add oil. Change if necessary. Drain. Refill with proper oil. See Low Oil Pressure for remedies.
Loose connecting rod. Low oil supply. Oil badly diluted.. Low oil pressure.
2 brands- Garretson: Replace rod bearings. Add oil. Change if necessary. Drain. Refill with proper oil. See Low Oil Pressure for remedies.
- NEC: Replace rod bearings. Add oil. Change if necessary. Drain. Refill with proper oil. See Low Oil Pressure for remedies.
Loose connecting rod, Low oil supply, Oil badly diluted.
1 brand- generatorpartspro: Adjust clearance or replace. Add oil. Change if necessary.
Defective intake valve stem cil seal, Worn intake valve, guide or valve stem, Faulty ignition, Oil leak from oil base or connections, Leaky crankshaft oil seals
1 brand- Hol-Gar: Inspect engine; check for clogged crank-case breather, Inspect oli seals, para 18b. (2) and 18e. (5). Check for clogged crankcase breather
Loose connecting rod bearing, Low oil supply, Low oil pressure, Oil badly diluted
1 brand- Cummins/Onan: Replace, Add oil, Refer to symptom of low oil pressure for remedies
Low oil supply. Oil badly diluted.
1 brand- Cummins/Onan: Add oil. Change oil.
Low oil supply, Oil badly diluted
1 brand- Cummins/Onan: Add oil, Change oil
Loose connecting rod bearing
1 brand- generatorpartspro: Replace unless one of the next two remedies permanently corrects the trouble
Loose connecting rod bearing, Low oil supply, Oil badly diluted
1 brand- Cummins/Onan: Adjust or replace connecting rod bearing, Add oil, Change oil
Loose connecting rod. Replace bearings unless one of the next two remedies permanently corrects the trouble.
1 brand- Cummins/Onan: Replace bearings necessary.
Loose connecting rod.
1 brand- Cummins/Onan: Adjust clearance or replace.
Inspect linkage and setting.
1 brand- Cummins/Onan: Clean & adjust carburetor.
Loose connecting rod bearing.; Low oil supply.; Low oil pressure. Refer to symptom of low oil pressure for remedies.; Oil badly diluted.
1 brand- Cummins/Onan: Adjust or replace.; Add oil.; Refer to symptom of low oil pressure for remedies.; Change oil.
Common questions
What causes light pounding knock?
Common causes, most-reported first: Loose connecting rod bearing.; Loose connecting rod. Low oil supply. Oil badly diluted.; Loose connecting rod. Low oil supply, Oil badly diluted. Low oil pressure.; Loose connecting rod. Low oil supply. Oil badly diluted.. Low oil pressure.; Loose connecting rod, Low oil supply, Oil badly diluted.; Defective intake valve stem cil seal, Worn intake valve, guide or valve stem, Faulty ignition, Oil leak from oil base or connections, Leaky crankshaft oil seals.