Controller displays “Overspeed” and shuts the engine down quickly after start; may be accompanied by high frequency readings.

Safety first: Do not attempt repeated starts. Turn generator OFF, open main breaker, and disconnect battery negative.

• Inspect throttle: Remove air intake ducting and verify that the throttle plate moves freely and returns to idle position when released. Clean carbon buildup if necessary.
• Governor linkage: Check that the governor arm is properly attached to the throttle and that no springs are missing or disconnected.
• Wiring: Inspect wiring from the controller to the governor actuator for damage or loose connectors.
• Controller diagnostics: Some Kohler controllers allow viewing of RPM or frequency. If readings are erratic, there may be a speed sensing issue (e.g., magnetic pickup sensor).

Because overspeed can cause catastrophic failure, further diagnosis and any governor module replacement should be performed by a Kohler-authorized technician.