Bowl Vent Solenoid: Description and Operation

Fig. 9 Carburetor fuel bowl solenoid vent valve:

This valve, Fig. 9, used on some vehicles, is a normally open valve located in the fuel bowl vent line to the carbon canister. When the engine is running, the valve closes off the fuel bowl vent line. When the engine is shut off, the vent line returns to the normally open condition.