Rich on Throttle in Carter 1-barrel Carbs


Runs rich under throttle in Carter W1, WA-1, WO, WDO 1-barrel carbs

Possible cause:

High fuel pump pressure

High float level

Warped or bent bowl cover allowing air leak at the gasket

Metering rod spring disconnected from metering rod

Metering rod not gauged properly

Worn metering rod and jet

Metering rod loose in casting

Metering rod disk missing on balanced vent carburetor (Chevrolet)

Bent metering rod

Damaged nozzle

Nozzle installed without nozzle gasket

Air bleed nozzles have to be installed with flat side of nozzle facing up, that is, when looking down from air horn.

A bowl cover with a vent hole, if installed on a balance vent carburetor, will cause a rich condition.

If relief check is stuck closed on carburetors that have relief check for accelerating pump or if the pump vent to the bowl is stopped up, the motor will draw gasoline through the pump system and the carburetor will run rich. If pump bushing gasket is missing, it will let gasoline splash from the bowl over on top of plunger causing pump to give high pressure.

Choker valve hinge stuck in air horn causing carburetor to be partly choked

Dirty air cleaner

Choke not operating properly

Air bleed in air bled nozzles stopped up

Choke shaft binds

Choke piston binds or is stuck

Air strainer gauze covered with dirt. This prevents hot air from reaching thermostatic coil.

Leak in tubing from stove to climactic control

Leak in choke gaskets

Choke valve binds in air horn

Cork disc in thermostat housing warped

Cork strip shrunk or interfering with operation of the thermostatic coil

Updated on 06/24/2022

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