Cummins/Onan — Fuel Connections
Installation · fuel system
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan HDKA, Cummins/Onan HDKAJ, Cummins/Onan HDKAK
Before you start
- Diesel fuel is a combustible and can cause severe personal injury or death. Do not smoke or allow any flame, spark, pilot light, arc-producing equipment, electrical switch or other ignition source around fuel or fuel components, or in areas sharing ventilation.
- Either or both engines could starve for fuel if the genset and vehicle engine fuel lines are interconnected. Always use separate fuel lines or a separate fuel tank for the genset.
Procedure
- Do not interconnect genset and vehicle engine fuel lines.
- Use separate fuel lines or a separate fuel tank for the genset.
- Do not extend the genset fuel pickup tube down into the fuel tank as far as the pickup tube for the vehicle engine.
- Fuel lines (supply and return) must have at least a 1/4 inch (6.4 mm) ID.
- Run the fuel line at or above the top of the fuel tank to reduce siphoning risk if the line should break.
- The maximum fuel pump lift is 36 inches (914 mm); use an auxiliary fuel pump kit for gensets mounted more than 36 inches above the fuel source.
- Route fuel lines away from electrical wiring and hot engine exhaust components.
- Secure fuel lines to prevent kinking, contact with sharp edges and chafing due to vibration.
Specs & values
- Fuel line ID: minimum 1/4 inch (6.4 mm)
- Maximum fuel pump lift: 36 inches (914 mm)
Full service-parts list: Cummins/Onan HDKA →, Cummins/Onan HDKAJ →, Cummins/Onan HDKAK →
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.