Check Valve Boat Gas Tank at rustynparkero blog

Check Valve Boat Gas Tank. Its purpose is to prevent fuel from starting a siphon. those are anti syphon valves.

Fuel Selector Valves
from www.cpperformance.com

if your gas tank is above your fuel pump, in overall height, then yes there will be an (or should be an) anti siphon. install a boat fuel vent check valve. Boats are required to use them to.

Fuel Selector Valves

Check Valve Boat Gas Tank those are anti syphon valves. Its purpose is to prevent fuel from starting a siphon. The vent is not venting. It is intended to keep fuel from running out of the tank if fuel line to motor leaks.