77' 140 fuel leaking at relief valve on back of fuel pump?

[i-anton-i]

First of all, Hello! I am new here. This site is great!

I have a 1977 Evinrude 140 that has a slow fuel leak at idle from the back side of the fuel pump out what I believe to be the relief valve. I have tried two different pumps and they both do the same. The diaphragms are in good shape on both pumps. It's as if the pump is building too much pressure and relieving it??? Let me say that this motor has an intake from a newer 115 so as to use the newer style shift rod from a newer lower unit. However, all that works fine and the motor runs great. Is it possible that this intake is supplying too much vacuum to the pump???

Any help greatly appreciated.
Cheers,
Tony

 

[david_r]

Re: 77' 140 fuel leaking at relief valve on back of fuel pump?

relief valve???

 

[i-anton-i]

Re: 77' 140 fuel leaking at relief valve on back of fuel pump?

I thought that?s what it was after taking the pump apart and looking at it. On the back of the bump there is this tiny white plastic thing that sticks out when the engine is running. Beside that there is a tiny hole. This is where the fuel is coming out.

That white thing has a spring on it when you take the pump apart and it looks like the spring is fighting against diaphragm pressure to open a passage to this tiny hole it the back portion of the pump.

 

[iwombat]

Re: 77' 140 fuel leaking at relief valve on back of fuel pump?

That's no relief valve - it's a diaphragm tensioner. Only way you get fuel out there is if the diaphragm is torn. Time for a fuel pump kit.

 

[i-anton-i]

Re: 77' 140 fuel leaking at relief valve on back of fuel pump?

In this picture you can see the white thing.

In this picture you can see the hole (from the inside) which the fuel is coming out of.

I borrowed thes pics from Theoutdoorsman's sticky post. I hope you don't mind.

 

[i-anton-i]

Re: 77' 140 fuel leaking at relief valve on back of fuel pump?

That's no relief valve - it's a diaphragm tensioner. Only way you get fuel out there is if the diaphragm is torn. Time for a fuel pump kit.

I buy that. Wasn't sure, that's why I was asking. I will get a rebuild kit Monday. I greatly appreciate your help. I should have looked closer at the diaphragm I guess. Maybe the next guy that thinks he knows somthing will see this and get set straight too. LOL...
Thanks,
Tony

 

[david_r]

Re: 77' 140 fuel leaking at relief valve on back of fuel pump?

heck i thought i missed something during my pump rebuild. i didnt remember what little thing with a spring you were talking about. so i went ot look at the faq from theoutdoorsman......and you had already posted the pics.


sorry i borrowed this comp from my mom and its a little slow....course i type(peck)slow too.

glad you got your answer