Generator display shows E15 and the unit shuts down; controller indicates a low frequency or underspeed condition.

Safety first: Disconnect nonessential loads and open the main breaker before testing. Keep clear of moving parts.

• Reduce load: Remove large loads from the standby circuit and restart the generator. If E15 does not return at reduced load, the generator was overloaded.
• Check governor linkage: Inspect the governor arm, linkage, and springs on the All Power America engine. Ensure nothing is binding and that the spring is intact. Adjust the governor per the service manual to restore correct speed.
• Verify fuel delivery under load: Check that fuel pressure and flow remain adequate when the generator is loaded. A restricted fuel filter or regulator can cause underspeed.
• Engine condition: If the engine cannot maintain speed even at moderate load, internal engine wear or valve issues may require professional repair.