Gas smell when engine off

Probably one of the lines going to the tank isn't tight or is broken or something, on top of the tank; or, the tank filler neck got cracked or there is a pinhole leak somewhere. Check to see if there is any gasoline stains after is has sit for a while. That would indicate a larger and more noticeable leak. If you do not see one then it may be a crack along the top somewhere are small enough like a pinhole that it is not leaving a puddle or stains anywhere. Smell = Leak somewhere.

OK thanks,