Dual tank fuel problem

[Papasteve54]

I have a 1968 Volvo penta 120 hp 4 cylinder engine. It sat for a few years so I took the tank out and had them flushed and pressure tested. Installed them replaced all fuel lines and new fuel pump. Rebuilt the carburetor. Put fuel in one tank only. When I prime the carburetor the engine fires right up but fuel is not pumping up to carburetor. Do I need to put fuel in the other tank

 

[alldodge]

I have a 1968 Volvo penta 120 hp 4 cylinder engine. It sat for a few years so I took the tank out and had them flushed and pressure tested. Installed them replaced all fuel lines and new fuel pump. Rebuilt the carburetor. Put fuel in one tank only. When I prime the carburetor the engine fires right up but fuel is not pumping up to carburetor. Do I need to put fuel in the other tank

Without a fuel valve, yes
The pump will draw from the path of least resistance. So it will draw air before fuel. If you install a 3 way valve it will work

 

[Papasteve54]

Without a fuel valve, yes
The pump will draw from the path of least resistance. So it will draw air before fuel. If you install a 3 way valve it will work

 

[Papasteve54]

Thanks for that it worked, dummy me. I had never started it without fuel in both tanks. Now it starts right up and purrs like a kitten at idle, but as soon as I go over 1000 RPM it craps out. I’ve never had to deal with carbs before