Cummins/Onan 6.3 NHEL / 6.5 NH — Governor Adjustments
Adjustments
For the Cummins/Onan 6.3 NHEL / 6.5 NH, from the Cummins/Onan service manual.
Applies to: Cummins/Onan NHEL
Before you start
- Use extreme caution when making adjustments while the engine is running; hot exhaust pipes or moving parts can cause severe personal injury.
Procedure
- Run unit about 10 minutes under light load to reach normal operating temperature.
- Adjust carburetor fuel mixture screws before governor adjustments.
- Adjust length of governor linkage and check for binding or excessive looseness.
- With engine stopped and tension on governor spring, adjust ball joint so throttle shaft stop almost touches carburetor stop.
- With warmed-up unit at no load, adjust speed adjustment nut to obtain 62 hertz and 127.5 (±4.5) volts.
- Check frequency and voltage first with load then with no load; must stay within Table 6-1 limits.
- Adjust governor sensitivity screw to give closest regulation without causing hunting (counterclockwise increases sensitivity).
- Recheck the speed setting and readjust if necessary.
- Set carburetor throttle stop screw as specified in Fuel System section.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 62 hertz / 127.5 ± 4.5 volts no load
- Max no-load speed 1890 rpm/63 Hz; min full-load speed 1770 rpm/57 Hz
Full service-parts list: Cummins/Onan NHEL →
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.