[deerejohnb]

I acquired a 1972 Evinrude Trailblazer this year and it needed a fuel pump. The old one was round, fairly large and mounted near the top of the hood. The fuel tank is in the front of the sled and the distance the fuel travels upward is quite steep.

I installed a mikuni fuel pump from a running arctic cat we have and I am having trouble keeping the fuel system primed with fuel. I need to crank the engine for a long time until fuel gets up there. Once its there, the engine runs great. However, when the engine is shut off, the fuel will slowly go back into the tank.

My question is do I need a bigger fuel pump or is the rectangular style mikuni adequate for this application. As I said the older one was bigger. If I need a bigger one, where could I get one. On the other hand maybe the pump I installed was just weak.

Any help would be greatly appreciated.

 

[RJ Gleason]

A round one for a twin carb set up will pull more fuel, but you will still run into the same problem.
What you need is a footvalve in the tank. This is a screened intake with a spring and ball valve in it that will only allow fuel to slow in one direction.

To test if you even have one on that line, unhook it from the pump and blow into it back to the tank. If you can blow the fuel out of the line, then you need a new one on there.

 

[deerejohnb]

Thank you for the info.

What I found was my brother purchased a filter assembly, but it didn't have the check valve inside it. I got one coming now.