Cummins/Onan — Mechanical Governor Adjustment
Adjustments
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Procedure
- Use the control frequency meter (if equipped) or an accurate tachometer.
- Loosen the speed adjustment screw locknut.
- Start the generator set, allow unit to warm up to proper operating temperature, then apply full rated load.
- Adjust the speed adjust screw in or out to reach required speed (60 Hz - 1800 r/min, or 50 Hz - 1500 r/min).
- Hold the speed adjust screw at proper setting and retighten the locknut.
- Remove and apply loads to check generator set response. Readjust the speed adjust screw if necessary. Contact your service representative if governor response is not satisfactory.
Tools required
- Frequency meter or accurate tachometer Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 60 Hz - 1800 r/min
- 50 Hz - 1500 r/min
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.