Cummins/Onan — Governor Speed and Sensitivity Adjustment
Adjustments
From a Cummins/Onan operator's manual covering: 12.0 DJC, 4.5 DJB, 4.5 DJE, 6.0 DJB, 6.0 DJE, 9.0 DJC. Check it applies to your exact model before use.
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Procedure
- Turn governor speed adjusting nut clockwise (more spring tension) to increase rpm, counterclockwise to reduce speed
- Use a stroboscope or frequency meter to make the adjustment
- Turn sensitivity adjusting ratchet counterclockwise for more sensitivity, clockwise for less
- Adjust for maximum sensitivity without hunting
- After sensitivity adjustment, readjust speed
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Preferred speed varies no more than 3 hertz from no-load to full-load
- 1800 rpm generates 60 hertz
Source: Cummins/Onan operator'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.