Cummins/Onan — Carburetor Assembly and Installation
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan NH engine
Procedure
- Install throttle shaft and plate with new screws and lock washers; center plate by tapping with a small screwdriver.
- Install the choke shaft and plate; center the plate the same manner as the throttle plate.
- Install the fuel inlet valve seat and valve.
- Install the float and float pin; center the pin so the float bowl does not ride against it.
- Check float level with the carburetor casting inverted.
- Install bowl ring gasket, bowl and bowl nut; tighten main jet assembly securely.
- Turn main jet in until it seats and back out 1 to 1-1/2 turns.
- Install idle adjusting screw finger tight, then back out 1 to 1-1/2 turns.
- Install the choke and adjust.
- Install carburetor on engine and connect gasoline inlet and governor mechanism.
- Install the air cleaner hose.
Tools required
- Small screwdriver Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Main jet 1 to 1-1/2 turns off seat
- Idle screw 1 to 1-1/2 turns off seat
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.