CARBURETED Engine
When engine is not running, vapor from expanding fuel in fuel tank collect in expansion tank. From the expansion tank, vapor flows out of tank and into charcoal canister through vapor separator and 2-way valve. The closed purge control valve prevents vapor from flowing out of canister and into intake manifold through purge line. When ignition is off, bowl vent solenoid valve opens to allow float bowl vapor to flow to canister.
When ignition is on, bowl vent solenoid valve closes, blocking off float bowl to canister passage. The thermo vacuum valve vents control vacuum to air cleaner until coolant temperature exceeds 95°F (35°C).
With engine running and coolant temperature greater than 95°F (35°C), thermo vacuum valve opens purge control valve. Manifold vacuum then pulls vapor from canister into combustion chamber for burning.