Cummins/Onan QST30 — Injector Installation
Repair & overhaul
For the Cummins/Onan QST30, from the Cummins/Onan owner's manual.
Applies to: Cummins/Onan G-Drive, Cummins/Onan QST30, Cummins/Onan QST30 engine
Before you start
- Wear protective clothing and eyewear when steam cleaning to prevent personal injury.
Procedure
- Use an injector bore brush to clean the injector nozzle bore.
- Check the inside of the nozzle holder sleeve for dirt or debris.
- Install new o-rings into the injector grooves; lubricate with clean engine oil.
- Confirm the seal ring is fitted to the tip of the injector.
- Inspect the bore in the cylinder head for debris.
- Align the fuel inlet connection hole to the opening in the rocker housing.
- Install the injector and the connector tube; hand tighten.
- Install the hold down clamp; torque to 65 N-m [48 ft-lb].
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Injector clamp capscrew 65 N-m [48 ft-lb]
- Connector tube 32 N-m [23 ft-lb]
- Locknut 32 N-m [23 ft-lb]
- High pressure fuel supply line 24 N-m [17 ft-lb]
Full service-parts list: Cummins/Onan QST30 →
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.