Cummins/Onan — Adjusting Gas Supply Pressure
Adjustments · Gas pressure regulator
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan Performer P224 engine
Before you start
- Gaseous fuels are flammable and explosive. Keep all ignition sources away. High gas supply pressure can cause gas leaks.
Procedure
- Close the gas supply shutoff valve.
- Remove the 1/8 inch pipe plug from the regulator test port and connect a manometer (scale range at least 14 inches WC).
- Open the gas shutoff valve and try starting the genset.
- While genset runs at no load, adjust the gas supply pressure regulator to obtain 11 inches (279 mm) WC.
- If genset will not start, jumper the fuel solenoid to the battery cable connections so it stays open, then check and adjust pressure.
- Check gas supply pressure under full load; low pressure may indicate undersized supply piping.
- Disconnect any jumpers and thread in and tighten the pressure test port plug.
Tools required
- Manometer (at least 14 inches / 350 mm WC) Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Gas supply pressure must be maintained at 9-13 inches (229-330 mm) WC
- Adjust to 11 inches (279 mm) WC at no load
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.