Generator runs but produces a loud knocking or metallic banging noise
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Immediately set the controller to OFF and open the generator AC breaker if you hear loud knocking. Do not continue to run the engine.
- Check oil level: After the engine cools, verify oil level and top up if low. If oil is very low or contaminated with metal, do not restart.
- Inspect flywheel: With the engine off and battery disconnected, remove the flywheel cover and ensure the flywheel nut is tight and the key is not sheared.
- Listen on restart (brief): If oil level is correct and no obvious issues are found, a brief restart may confirm if the knock persists. Shut down immediately if it does.
Internal engine knocks usually indicate serious damage and require engine teardown or replacement by a qualified technician.
Repair Difficulty
Required Part
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