Evaporative Emissions System: Description and Operation

Fig. 9 Evaporative emission control system.:

I-MARK

The evaporative emission control system, Fig. 9, is designed to direct raw fuel vapors emitted from the fuel tank and carburetor to the crankcase and charcoal canister respectively. The fuel vapors directed into the crankcase are mixed with blow-by gasses and are drawn into the intake manifold, where they are ignited. Vapors stored in the charcoal canister are mixed with ambient air and are routed to the intake manifold only when the engine is running. This system consists of a vapor separator tank, a check and relief valve, a vent switching valve, a charcoal canister and ventilation valve used on some models.