1956 Evinrude Pressure Tank Leaks

[twier]

Hopefully this brain trust will have a couple of ideas!

I have a 1958 Evinrude Big Twin 35 with a 1956 pressure tank. I have put in all the typical rebuild kits for both tank and motor.

My current problem is the tank (new gaskets and o-rings). I pump the primer button and gas comes out the tank just fine, out the hose through the quick connect, and into the fuel filter bulb. About the time it starts running into the carb the primer button on the tank leaks significantly. I suspected the little check valve in the fuel pickup line but I loosened it up and got it to rattle when you shake the tube. This part is still my suspicion but a new one is $90. Any ideas on how to trouble shoot?

Thanks Terry

 

[F_R]

That is an extremely common problem. The fluid is passing through the diaphragm hole where the button push rod goes through. There are a couple of reasons it happens.
1 Bent or rusted diaphragm support washers.
2 Bottom end of push rod is corroded. It must be flat to seal where it contacts the upper diaphragm support washer.
3 Use a small dab of fuel-proof sealer where the push rod contacts the washer, just for good measure.
4 The knob is supposed to spin freely on the push rod. If it does not, you tend to rotate it as you pump. That unscrews the nut at the bottom end.

Save your money, it IS NOT the fuel pickup tube

 

[twier]

F_R,

Many thanks, the sealer did the trick. And the Big Twin started for the first time in who knows when! I now need to wait until I can get it outside to dial in the needle valves (just about gassed myself in the basement today).

 

[jimmbo]

Dialing in the needle valves needs to be done in the water, under load. Translation... On a boat in the water. Otherwise the settings will be wrong