The carbon canister is designed to soak the fuel vapours from the fuel tank when the engine is turned off or parked in a hot or cold location. Over time the fuel may expand and the vapours are soaked up by the carbon canister. When the engine starts the vacuum will draw the vapours, recycle them, and prevent the vapours from entering the atmosphere.
THINGS TO LOOK FOR
The carbon canister may be full of petrol if the fuel tank ...