Cummins/Onan — Overhead Set - Adjust Valves and Injectors
Adjustments · Valve and injector overhead
From a Cummins/Onan owner's manual covering: QSM11, QSM11 Industrial, QSM11 Marine, QSM1i. Check it applies to your exact model before use.
Applies to: Cummins/Onan QSM1i, Cummins/Onan QSM11 engine
Before you start
- All valve and injector adjustments must be made when the engine is cold (below 60°C).
Procedure
- Remove crankcase breather tube and rocker lever cover.
- Rotate accessory drive to the A valve set mark aligned with pointer.
- Loosen injector adjusting screw locknut; bottom the plunger 3 or 4 times.
- Back out adjusting screw two flats (120 degrees); tighten locknut to 61 N·m.
- Loosen intake and exhaust valve adjusting screw locknuts.
- Insert correct feeler gauge between crosshead and rocker lever pad.
- Tighten adjusting screw (torque wrench method 1 N·m) and hold.
- Tighten valve locknut to 61 N·m (47 N·m with adapter); recheck feeler gauge.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Intake 0.36 mm
- Exhaust 0.68 mm
- Injector locknut 61 N·m
Full service-parts list: Cummins/Onan QSM1i →
Source: Cummins/Onan owner'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.