Cummins/Onan 4MCCK / 605MCCK — Governor Adjustment
Adjustments · Governor and vacuum booster
For the Cummins/Onan 4MCCK / 605MCCK, from the Cummins/Onan service manual.
Applies to: Cummins/Onan 605MCCK, Cummins/Onan MCCK, Cummins/Onan MCCK engine
Procedure
- Run the plant 15 minutes under light load to reach normal operating temperature.
- Adjust the carburetor main jet for best fuel mixture at full rated load.
- Adjust the carburetor idle needle under no-load condition.
- Adjust the length of the governor linkage.
- Check the governor linkage and throttle shaft for binding or excessive looseness.
- Adjust the governor spring tension for rated speed at no-load with the booster disconnected.
- Adjust the governor sensitivity.
- Recheck the speed adjustment.
- Set the carburetor throttle stop screw.
- Set the vacuum speed-booster.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- The governor should not allow more than 2-1/2 cycles change from no-load to full-load
Full service-parts list: Cummins/Onan 605MCCK →, Cummins/Onan MCCK →
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.