Prevent engine flooding that is a result of new EPA required closed fuel systems. EPA requirements for portable fuel systems no longer permit vapor emissions or ventilation into the atmosphere. As a result, these closed systems can build up pressure in the tank that forces fuel into the engine causing it to flood and leak into the water. West Marine Fuel Demand Valves (FDV) control the added pressure in these systems and eliminate engine flooding and potential fuel spray while connecting and disconnecting fuel lines at the engine. The fuel demand valve can hold up to 5psi of pressure and allow the engine to draw only what it needs without impeding normal fuel flow. To address similar pressure issues at the tank, we recommend the installation of a sprayless connector and fitting at the tank end. Key Features Prevents engine flooding caused by added pressure in ventless fuel systems Controls pressure to eliminate risk of fuel spray when connecting and disconnecting fuel lines at the engine Allows engine to draw at normal fuel flow rate Compatible with ethanol blending fuels Fits 5/16" and 3/8" fuel hose