Carburetor Venting

Fuel vapors which might otherwise collect in the carburetor bowl and pass directly into the atmosphere are vented to the carbon canister when engine is stopped. Flow of these vapors is controlled by the fuel bowl vent valve, the purge control valve, or the fuel bowl thermal vent valve, depending on the particular carburetor and engine calibration used. When the engine is started, and depending on the operating mode when purging the system is most efficient, the vapors will be drawn into the engine for burning.