Cummins/Onan 4.0 MCCK / 6.5 MCCK — Governor Adjustment
Adjustments
For the Cummins/Onan 4.0 MCCK / 6.5 MCCK, from the Cummins/Onan operator's manual.
Applies to: Cummins/Onan MCCK engine
Before you start
- An adjustment for too much sensitivity will cause alternate increase and decrease of engine speed (hunting).
Procedure
- Run set about 15 minutes with light load to reach normal operating temperature.
- Adjust carburetor main jet for best fuel mixture at full rated load.
- Adjust carburetor idle needle with no load connected.
- Adjust length of governor linkage; check linkage and throttle shaft for binding or excessive looseness.
- Adjust governor spring tension for rated speed at no load.
- Adjust governor sensitivity.
- Recheck the speed adjustment.
- 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
- Throttle stop: 56 hertz at no load
- No-load speed 1890 rpm / 63 Hz; full-load 1770 rpm / 59 Hz
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.