Gasoline Models

System is designed to route fuel vapors from fuel tank and carburetor into carbon canister where they are stored until intake vacuum draws vapor into combustion chambers for burning.

System components vary by model. See Figure &Figure . Components include a sealed filler cap, vapor separator, check and relief valve, canister and purge control valve, vent valve, vent switching valve (solenoid operated), relief valve, roll-over and float valve, 2-way valve, and connecting lines and hoses.

Some models use a roll over and float valve and relief valve to prevent fuel leakage and excessive pressure inside fuel tank in the event of a vehicle roll over. These valves are not relevant to fuel evaporation system.