Controller shows 'Underfrequency' or 'Low Hz'; transfer switch may drop load.

Safety first: Isolate the generator from the load. Turn OFF the unit and disconnect battery negative before mechanical adjustments.

Steps:

• Reduce load: Remove non-essential loads and see if frequency returns to normal. If it does, the generator was overloaded.
• Check fuel and air: Inspect air filter, fuel pressure, and fuel line for restrictions. Correct any issues.
• Governor linkage: Inspect and clean the governor linkage and throttle plate. Ensure there is no binding and that springs are intact.
• Frequency measurement: With a meter capable of reading Hz, verify actual frequency at the generator output. If the controller reading is wrong but frequency is correct, the sensing circuit or controller may be faulty.
• Professional adjustment: Fine-tuning governor speed should be done by a technician to avoid overspeed conditions.