The Stovebolt Site Forums The Shop Area Engine Shop 41 with 235 fuel line

I am plumbing from tank to fuel pump, I was going to use 1/4 steel Tubing then I saw the line from pump to carb was 5/16. What is the best here? Should I also put a filter before pump? Do I need any flex in this line? Dave

Dave.
My 46 is 5/16" from tank to pump. The only flex line, about 14", is from the tank to the 5/16" line. I also installed a filter prior to the pump. This will catch any "trash" before it messes up the pump. The pump to carb is also 5/16".

The pump will need these fittings in & out to connect to the 5/16" line fitting
Harold

The valve I wanted to use on the outlet of the tank has 1/4 inch tube outlet.

Valve?

Can you give more details on that?

The valve is brass, has 1/8" mnpt into the tank and a compression fitting,1/4" on the outlet. It works like the drain on the radiator or an engine block

Please someone correct me if I am wrong but I was told if your running a mechanical fuel pump you want to put the fuel filter after the fuel pump because a mechanical pump pushes fuel better through the fuel filter than it sucks the fuel filter before the mechanical fuel pump. It will also help keep it from vapor lock. If your running an electric fuel pump you want to put the fuel filter before the fuel pump.

Just a thought.

Mechanical pump is a diaphragm and some check valves. The check valves are ball bearings that open when the diaphragm is pushed away from the check valve. So it "sucks" fuel from the tank and "pushes" fuel to the carb. Any dirt will stop the check valve from seating. That would let fuel get "pushed" back to the tank, and "sucked" from the carb. Not the way you want it to work. A filter inline from the tank to the pump is just insurance that the pump will work as it was intended. Won't hurt anything. And it could help. Electric pumps have an impeller to push fuel to the engine. Dirt will destroy that in short order. So a filter between the tank and pump is standard. I like a clear filter that I can see the dirt in. Lets me know when it needs to be changed. A filter inline from the pump to the carb is to protect the carb. Again, I like a clear filter that lets me see what is in there. And yes, I run both. The filter won't care if fuel is pushed through it or sucked through it. Only issue would be if it leaks. Most of the movement is very low pressure hydraulic any way. If you take the fuel line off the pump with a full tank of gas it will run out like crazy if you don't cap the line.

I like the original design fuel pump with the glass bowl with filter screen to keep the big chunks out of the check valves. And it looks cool.

Dave,
Perhaps these photos will help you. The single Brass Fitting is the one I told you about in my first reply.
Flex Line
I reused the original shut-off valve. I suggest you take your shut-off valve with you to make sure the threads match up. I used a fuel line from NAPA (Fuel Line Pump To Tank 5/16" X 60") P/N 813-5471. Good luck with you restoration.
Harold

Is there any reason not to run flex hose all the way from tank to fuel pump? Dave

only that flexible rubber hoses are more prone to deterioration, kinking, abrasion damage, and internal failures, your choice

Bill

I replaced the shutoff valve under the gas tank with a sediment bowl filter that had a shutoff valve and a clear glass bowl. It screws directly into the gas tank. It catches everything before it gets to the gas pump. The pump also had a clear sediment bowl on it. I clean the bowl under the tank periodically, I never see anything in the one on the pump. The shutoff valve makes it convenient for cleaning purposes.