Cummins/Onan — Gas Regulator Adjustment
Adjustments
From a Cummins/Onan service manual — check it applies to your exact model before use.
Browse Cummins/Onan generators & specs →
Before you start
- Soap bubble test is not accurate; use manometer.
Procedure
- Use manometer reading up to 14 inches water column.
- Remove 1/8 inch pipe plug C and connect manometer.
- With gas on and hose removed, alternately cover and uncover regulator outlet with hand.
- If manometer holds steady, regulator locks off. If reading drops, regulator leaking.
- Adjust lock-off screw G inward just enough so manometer reading remains constant.
- Operate engine to insure quick starting.
Tools required
- manometer Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- lock-off pressure 4 ounces (7 inch water column)
- incoming pressure 2-4 ounces
- 1 ounce = 1.73 inches water column
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.