No charcoal canister in the tank it has a rollover valve and if the tank is over filled it will draw fuel right into the air filter housing and flood the engine. They put the valve in the tank and expect people to read the instruction manual and not over fill it. I have seen the tank filled so full it will shoot raw fuel out the exhaust pipe on the muffler. Manufactures need to redesign the system and get the rollover valve out of the tank. But then again people will still fill the tank too full and when it is cool is all right and when the mower sets in the sun and heats up the fuel will expand and it can do the same thing.