Refueling

I found out that the regular ole fuel pump (4 to 6 psi as I recall) does have a check valve in it. However it is checked for back flowing since it needs to be that way for feeding a carburetor. I found that the check valve would let the gas siphon forward since the tank filler neck is below the aux tank level. Installing a 12 volt normally closed valve in the transfer line between the pump and filler neck inlet will solve this problem. Also by shutting the fuel off that way the vehicle system automatically goes to a closed system when the pump is turned off. For me that eliminated the need for the return line.

Also there is s handy little electronic gizmo out the re that will allow you to adjust how long the fuel pump will run after it is switched on.