Cummins/Onan — Adjust valve clearance
Adjustments · valve train
From a Cummins/Onan service manual covering: 10MJC, 15MJC, 3MJA, 4MJA, 5MJB, 705MJB. Check it applies to your exact model before use.
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Procedure
- Warm engine to room temperature (70°F).
- Rotate flywheel so cylinder is 10° to 45° past TDC compression.
- Loosen rocker arm nut.
- Insert feeler gauge of specified clearance.
- Tighten rocker arm nut.
- Recheck clearance.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- See valve clearance chart
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.