Vapor Vent Control Valve

Attach a short piece of hose to carburetor bowl vapor tube of canister and attempt to blow through it to determine if air will pass vapor vent valve into canister. If not possible to blow into canister, it must be replaced.
Using hand vacuum pump, apply 15 in. Hg to vacuum signal tube in diaphragm assembly cover. If diaphragm does not hold vacuum for at least 20 seconds, diaphragm is leaking, and canister must be replaced.
With vacuum still applied, again attempt to blow into the carburetor bowl vapor tube of the canister. Air should pass vapor vent valve into canister, indicating that valve is sealing properly.
If air does enter canister past vapor vent valve, valve is not functioning properly and canister must be replaced.