Nexus
Overspeed
Overspeed
Engine · Alarm
Nexus overspeed is a named alarm. During cranking and running, the controller reads speed from the ignition magneto on wire 18. The manual says that if speed exceeds approximately 72 Hz (4320 rpm), it de-energizes the run relay, which kills ignition and closes the fuel shutoff solenoid.
Seen on: Air-cooled generators with the Nexus controller covered by the Nexus diagnostic manual.
Likely causes
- Engine speed actually above about 72 Hz.
- A governor or throttle problem that lets it run away. The Nexus page does not use the Evolution stepper e-code numbers.
Checks an owner can do
- Do not restart a set that shut down for overspeed.
When to call a pro
Overspeed can damage the engine and alternator. A technician has to find why speed exceeded about 72 Hz before it is returned to Auto.
Source
Wording follows that document. Firmware can change a threshold. If this page and the manual shipped with your unit disagree, follow the manual.
What fixed mine
No approved reports for this code yet. Send one. It stays in the review queue until it is approved.
Related Generac codes
https://generatorcodes.com/brand/generac/nexus-overspeed