Generator runs but output voltage is low; controller may show 'Undervoltage' or transfer switch refuses to transfer load.

Safety first: Isolate the generator from the home by opening the main generator breaker. Turn OFF the unit and disconnect battery negative before internal inspection.

Steps:

• Check engine performance: Listen for bogging or misfiring under load. If the engine cannot maintain RPM, address fuel/ignition issues first.
• Inspect alternator connections: Tighten all lugs at the alternator output terminals and at the internal breaker. Look for heat discoloration or melted insulation.
• Inspect AVR: Check the AVR for burnt components or odor. Reseat connectors.
• Voltage test: With a meter and proper PPE, run the generator unloaded and measure voltage. If low even with a healthy engine, replace the AVR with the correct Honeywell part.
• Further diagnosis: If voltage remains low after AVR replacement, the alternator stator or rotor may be damaged and should be tested by a generator technician.