The Carbon Canister was fitted first to 1975 B210 to capture fumes from the fuel tank. Instead of letting the fumes just to go the atmosphere. In the Canister is an activated charcoal filter. Later when the engine runs, fresh air is drawn through the filter and burned in the engine. Like all 1200s, the fuel tank Filler Cap is not vented. It seals the gas tank well, so that any fumes must go through the vent hose. In the case of EVAPO models, the tank is vented in the engine compartment through a steel Evaporative Fuel Line.
Makes your Sunny smell good!
Fuel tank vents to the canister, like this through the Evaporative Fuel Line (tank vent line):
The 1.5-way check valve lets fresh air freely into the tank, but only a little of the fumes from the tank can go back into the engine compartment.
The canister has three lines like this:
- Purge line (to intake manifold)
- Control line (to "ported vacuum" fitting high up on carburetor, perhaps same as EGR port)
- Vent line to tank. Vent line includes the Fuel Check Valve (1.5-way valve)