Cummins/Onan 5.5 NH / 6.5 NH — Break-in Procedure
Operation · engine
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
- Failure to follow the recommended break-in procedure may result in poor piston ring seating.
Procedure
- One-half hour at 1/2 load (approximately 3,250 watts).
- One-half hour at 3/4 load (approximately 4,875 watts).
- Change crankcase oil after the first 25 hours of operation.
- Use regular grade leaded gasoline for the first 25 hours of operation.
- Avoid running for extended periods without load, especially during the first 50 hours.
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.