Mercury - Fuel Tank Connection with Fuel Demand Valve Portable Fuel System Marine-Grade Construction 8M0054713. Overview. Anyone who's spent time on the water knows how much confidence comes from a fuel system that behaves exactly the way it should. No surprises. No sudden sputter right when you're lining up a drift or easing away from the dock. The Quicksilver 8M0054713 Fuel Tank Connection with Fuel Demand Valve brings that quiet reliability you can feel in your shoulders-the kind that lets yo