Controller displays HF and generator shuts down or refuses to transfer load.

Safety first: Disable automatic operation and keep clear of moving parts. Overspeed can cause dangerous mechanical failure.

• Visual governor check: With engine off, inspect the governor arm, springs, and linkage. Ensure the correct Briggs & Stratton governor spring is installed and not stretched or incorrectly hooked.
• Throttle plate movement: Manually move the carburetor throttle lever. It should move smoothly and return to idle by spring force. Clean any carbon or debris around the throttle shaft.
• Electronic governor (if equipped): On models with an electronic actuator, inspect the actuator linkage and electrical connector. If the actuator is stuck or buzzing erratically, it may be failing and require replacement.
• Controller settings: Verify that no unauthorized changes have been made to frequency or speed calibration in the controller menu. Restore factory defaults if necessary per the service manual.
• Clear the code: After repairs, cycle to OFF then AUTO and test in MANUAL while monitoring frequency with a meter.