Generator is excessively noisy during operation compared to normal, with rattling or metallic sounds.

Safety first: Turn OFF the generator, disconnect battery negative, and allow hot components to cool.

• Inspect engine mounts: Check all engine and alternator mounting bolts for tightness. Tighten to Yamaha torque specifications.
• Check exhaust system: Inspect the exhaust manifold, flex pipe, and muffler brackets for loose fasteners or cracks. Tighten or replace hardware as needed.
• Examine vibration isolators: Look for torn or collapsed rubber engine mounts. Replace any damaged isolators.
• Run test: Restart the generator and listen for remaining abnormal noises. Persistent internal knocking or grinding should be evaluated by a Yamaha technician.