Cummins/Onan — Carburetor Overhaul (Prior to Spec G)
Repair & overhaul · Gasoline carburetor
From a Cummins/Onan service manual covering: P216, P218, P220, P248. Check it applies to your exact model before use.
Applies to: Cummins/Onan P216, Cummins/Onan P218, Cummins/Onan P220, Cummins/Onan P248
Before you start
- Ignition of fuel can result in severe personal injury or death. Do not smoke or allow any flame, spark, pilot light, or other source of ignition near the work area.
- Overtightening the mixture adjustment screw will cause carburetor damage.
Procedure
- Remove the air cleaner assembly; disconnect the throttle linkage, choke control, and fuel line; remove the carburetor from the intake manifold.
- Remove the main jet and idle adjustment needle.
- Remove the attaching screws and separate the upper and lower carburetor sections.
- Note the float assembly positions, pull out the retaining pin and float assembly, then remove the needle valve.
- Soak all metal components not replaced in carburetor cleaner; do not soak non-metal floats or other non-metal parts.
- Clean carbon from the carburetor bore, especially where the throttle and choke plates seat; do not plug idle or main fuel ports.
- Dry out all passages with low pressure air (35 psi); avoid wire or objects that could enlarge critical passages.
- Replace a damaged adjustment needle; replace a float loaded with fuel or damaged.
- Install the needle valve, main jet, and float assembly; make sure the float pivot pin is properly placed and the float moves freely.
- Position the gasket on the lower section and install the upper carburetor section; install idle adjustment screw, throttle stop screw, and fixed main jet plug.
- Mount the carburetor on the intake manifold, install on the engine, connect governor and throttle linkage, choke control, and fuel line, and mount the air cleaner.
- Adjust the carburetor and governor according to directions in this section.
Tools required
- screwdriver with 5/16-inch (8-mm) wide blade Amazon
- low pressure air source (35 psi) Amazon
- carburetor cleaner Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Dry passages with low pressure air (35 psi)
- If replacing the idle mixture screw, turn in until lightly seated, then back out 1-1/4 turns
- Float level measured from top of carburetor body to top of float
Full service-parts list: Cummins/Onan P216 →, Cummins/Onan P218 →, Cummins/Onan P220 →, Cummins/Onan P248 →
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.