Cummins/Onan — Governor Calibration Checks
Adjustments · Electronic governor
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan DFAA, Cummins/Onan DFAB, Cummins/Onan DFAC, Cummins/Onan DFBF, Cummins/Onan DFCB, Cummins/Onan DFCC, Cummins/Onan DFCE, Cummins/Onan DFE
Procedure
- Start the generator set.
- Adjust engine no-load speed to the desired allowable speed droop using the Run Speed potentiometer.
- With no load, turn GAIN clockwise slowly until engine speed oscillates.
- Reduce GAIN slowly counterclockwise until engine speed is stable.
- Upset the governor by momentarily shorting terminals 7 and 10 on the governor control.
- Apply and remove loads to check generator set response.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Isochronous: 60.0 Hz/1800 r/min (50.0 Hz/1500 r/min)
- 3% droop: 61.8 Hz/1854 r/min (51.5 Hz/1545 r/min)
- 5% droop: 63.0 Hz/1890 r/min (52.5 Hz/1575 r/min)
- If speed oscillates up to 3 diminishing oscillations and stops, the setting is correct.
Full service-parts list: Cummins/Onan DFBF →, Cummins/Onan DFCC →, Cummins/Onan DFCE →, Cummins/Onan DFE →
Source: Cummins/Onan service 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.