The generator runs sluggishly, may stall under load, and displays 'Underspeed' or a low frequency alarm.

Safety first: Turn OFF the generator and disconnect the battery negative terminal. Shut off gas before working on fuel components.

Steps:

• Check air filter: Remove and inspect the air filter. Replace if dirty or oil-soaked.
• Inspect fuel supply: Confirm gas valves are fully open and that fuel pressure is within specifications. Look for a kinked or damaged fuel hose to the engine.
• Clean throttle and linkage: Inspect the throttle body or carburetor and governor linkage for carbon buildup or corrosion. Clean with appropriate cleaner (engine off) and ensure free movement.
• Light load test: After reassembly, reconnect the battery, clear the alarm, and run the generator with no load. If it runs normally, gradually add load and observe. Persistent underspeed under modest load indicates deeper fuel or engine issues requiring professional service.