Cummins/Onan — Governor Adjustments
Adjustments
From a Cummins/Onan service manual — check it applies to your exact model before use.
Browse Cummins/Onan generators & specs →
Before you start
- Touching hot exhaust pipes or moving parts might result in serious personal injury. Use extreme caution when making adjustments while engine is running.
Procedure
- Run unit about 10 minutes under light load to reach normal operating temperature.
- Adjust carburetor idle and main adjustment screws before governor adjustments.
- Adjust length of governor linkage; check for binding or excessive looseness.
- With engine stopped and tension on governor spring, stop on throttle shaft almost touches carburetor stop.
- With warmed up unit at no load, adjust governor spring tension to obtain 127 volts and 61 hertz.
- Check voltage and speed with load and no load; adjust sensitivity to closest regulation without hunting.
- To increase sensitivity, shift spring toward governor shaft.
- Recheck speed adjustment; set carburetor throttle stop screw as specified.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 127 volts and 61 hertz no load
- Maximum no-load voltage 132
- Minimum full-load voltage 108
- Maximum no-load speed 1890 RPM / 63 Hz
- Minimum full-load speed 1770 RPM / 57 Hz
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.