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 the engine is stopped.

Flow of these vapors is controlled by a fuel bowl vent valve or a fuel bowl thermal vent valve, depending on the particular carburetor and engine calibration used.

When the engine is started, the vapors will be drawn into the engine for burning. The time at which the vapors are drawn into the engine will depend on the operating mode of the engine when the purging system is most efficient.