Cummins/Onan — Priming the High Pressure Fuel System
Maintenance · Fuel injection system
From a Cummins/Onan owner's manual covering: 4A2.3, 4A2.3-GS/GC, 6A3.4-GS/GC-1, 6A3.4-GS/GC-2, 6AT3.4-GS/GC, ES-1788. Check it applies to your exact model before use.
Applies to: Cummins/Onan ES-1788, Cummins/Onan 4A2.3 engine
Before you start
- Fuel is under extremely high pressure and can penetrate skin causing blood poisoning or infection. Wear protective gloves and face mask.
Procedure
- Loosen fuel injection line connecting nut at each nozzle holder.
- Energize starting motor by placing Run/Stop/Remote switch in Run position.
- After 30 seconds, place switch in Stop and pause two minutes to cool starter.
- Discontinue priming when fuel flows from all high pressure lines.
- Tighten connection nuts and torque to 18 ft-lbs (24 N·m).
Specs & values
- Injection line connecting nut torque: 18 ft-lbs (24 N·m)
Full service-parts list: Cummins/Onan ES-1788 →
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.