Cummins/Onan 5.5 NH / 6.5 NH — Governor Adjustments
Adjustments
For the Cummins/Onan 5.5 NH / 6.5 NH, from the Cummins/Onan operator's manual.
Applies to: Cummins/Onan NH engine
Before you start
- Touching hot exhaust pipes or moving parts might result in serious personal injury. Use extreme caution when making adjustments while the engine is running.
Procedure
- Run the unit about 10 minutes under light load to reach normal operating temperature.
- Adjust the carburetor idle and main adjustment screws as specified in the Mixture Screw Adjustments section.
- Adjust the length of the governor linkage and check for binding or excessive looseness; adjust ball joint so the throttle shaft stop almost touches the carburetor stop.
- With the warmed-up unit at no load, adjust governor spring tension to obtain 127 volts and 61 hertz.
- Check voltage and speed with load and without load; adjust sensitivity for closest regulation without hunting.
- Recheck the speed adjustment, then set the carburetor throttle stop screw.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- No-load setting: 127 volts and 61 hertz
- Maximum no-load speed 1890 r/min (63 hertz)
- Minimum full-load speed 1775 r/min
- Maximum no-load voltage 132, minimum full-load voltage 108
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.