Cummins/Onan — Overspeed Setpoint Adjustment and Testing
Adjustments · Electronic overspeed switch
From a Cummins/Onan owner's manual covering: 6CTA8.3, CFP83-F10, CFP83-F20, CFP83-F30, CFP83-F40. Check it applies to your exact model before use.
Applies to: Cummins/Onan 6CTA8.3, Cummins/Onan CFP83-F10, Cummins/Onan CFP83-F20, Cummins/Onan CFP83-F30, Cummins/Onan CFP83-F40, Cummins/Onan 6CTA8.3G2 engine, Cummins/Onan 6CTAA8.3G3 engine
Before you start
- Do not exceed 120% of rated speed.
Procedure
- Lower the cover on the engine's local control panel.
- Disconnect the engine speed sensor signal from PICK-UP terminals 1 and 2.
- Connect a signal generator capable of providing 0.25 to 120 VAC RMS proportional to the engine's rated speed.
- Remove the calibrating screw cover from the electronic overspeed switch.
- Turn the potentiometer screw clockwise to increase trip speed, counter-clockwise to reduce trip speed.
- Adjust until the OVERSPEED light is just illuminated at the desired setpoint.
- Replace the screw cover, disconnect the signal generator, reset the light, and reconnect the speed sensor input.
Tools required
- Signal generator (0.25 to 120 VAC RMS) Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Overspeed setpoint must be set between 115 and 120% of the engine's rated speed
- TEST button lowers the currently adjusted overspeed by 10%
Full service-parts list: Cummins/Onan CFP83-F10 →, Cummins/Onan CFP83-F20 →, Cummins/Onan CFP83-F30 →, Cummins/Onan CFP83-F40 →
Source: Cummins/Onan owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.