Generator starts but immediately surges, hunts, or stalls under light load with no error code.

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

• Inspect air filter: Replace a dirty air filter element to ensure proper airflow.
• Check throttle linkage: Move the throttle and governor linkage by hand to ensure smooth travel. Clean and lightly lubricate pivot points.
• Clean carburetor/throttle body: Remove the air intake duct and spray Yamaha-approved carburetor or throttle body cleaner into the throttle bore while manually operating the throttle. For severe contamination, remove and disassemble the carburetor for thorough cleaning or replace it.
• Fuel quality: Drain old fuel and refill with fresh, Yamaha-recommended fuel. Add fuel system cleaner if appropriate.