Cummins/Onan QST30 / QST30 G-Drive — Fuel Pump Installation (Coupling Drive)
Repair & overhaul · Injection Pump
For the Cummins/Onan QST30 / QST30 G-Drive, from the Cummins/Onan service manual.
Applies to: Cummins/Onan QST30, Cummins/Onan QST30 engine
Before you start
- Severe damage to the fuel pump will occur unless the fuel pump is unlocked prior to operation.
Procedure
- Rotate the engine slowly clockwise to align the timing mark on the crankshaft damper with the timing pointer; ensure #1 cylinder (right bank) is on the compression stroke.
- Remove the timing pin cap and verify that the pump is locked.
- Install the timing pin (1), cap (2) and sealing washer (3); torque to 30 N-m [22 ft-lb].
- Set the in-line fuel injection pump assembly in position at an angle with the bracket partially installed.
- Tighten the four injection pump bracket mounting bolts (2) and four pump mounting bolts (4); torque 66 N-m [49 ft-lb].
- Tighten the coupling bolts (1); torque 108 N-m [80 ft-lb].
- Install the high pressure fuel lines (3); torque 24 N-m [17 ft-lb].
- Install the fuel pump drain line and fuel return tube (2); torque 9 N-m [80 in-lb].
- Install the injection pump drive shaft cover (1).
- Install the low pressure fuel lines (2); torque 24 N-m [17 ft-lb].
- Install the oil lines (3); torque 27 N-m [20 ft-lb].
- Install the electrical connection (1).
- Unlock the fuel pump timing prior to operation.
Specs & values
- Timing Pin Cap 30 N-m [22 ft-lb]
- Pump Mounting Bolts 66 N-m [49 ft-lb]
- Bracket Mounting Bolts 66 N-m [49 ft-lb]
- Coupling Bolts 108 N-m [80 ft-lb]
- High pressure fuel lines 24 N-m [17 ft-lb]
- Drain line/return tube 9 N-m [80 in-lb]
- Low pressure fuel lines 24 N-m [17 ft-lb]
- Oil lines 27 N-m [20 ft-lb]
Full service-parts list: Cummins/Onan QST30 →
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.