### Evaporative Emission Control System

When raw fuel evaporates, the vapors contain hydrocarbons. To prevent these fumes from escaping into the atmosphere, the fuel evaporative emission control system was developed.

The system consists of a sealed fuel tank, a vapor/liquid separator (certain models only), a vapor vent line, a carbon canister, a vacuum signal line and a canister purge line.

In operation, fuel vapors and/or liquid are routed to the liquid/vapor separator or check valve where liquid fuel is directed back into the fuel tank as fuel vapors flow into the charcoal filled canister. The charcoal absorbs and stores the fuel vapors when the engine is not running or is at idle. When the throttle valves in the carburetor (or air intakes for fuel injection) are opened, vacuum from above the throttle valves is routed through a vacuum signal line to the purge control valve on the canister. The control valve opens and allows the fuel vapors to be drawn from the canister through a purge line and into the intake manifold and the combustion chambers.