Cummins/Onan — Break-In Procedure
Operation · engine
From a Cummins/Onan service manual — check it applies to your exact model before use.
Browse Cummins/Onan generators & specs →
Before you start
- Improper break-in can cause severe cylinder scoring, bearing galling, cylinder wall glazing and poor piston ring seating.
Procedure
- Run engine at about half load for 30 minutes.
- Run at three-quarter load for another 30 minutes.
- Apply varying loads including intermittent full load for next four hours.
- Do not bog engine down or exceed full nameplate horsepower rating.
- Drain oil at end of 5 hour period and refill.
- Thereafter check oil as prescribed in maintenance schedule.
Specs & values
- 5 hour break-in period
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.