Possible fuel pressure problems

[JoshT]

I rebuilt the 2.8 in my truck a little while back and never took the time to properly set up the carburetor. Well now that I'm trying I seem to be having trouble with fuel coming out of the front Bowl Vent on my Holley 390cfm. I've tried adjusting the float level all through it's range, even tried to adjust the float itself to close the valve sooner. At this point I'm thinking that the fuel pressure may be forcing it's way past the valve seat. If this is the case the only course of action I can think of would be a fuel pressure regulator but with the ratings on the things I don't know which I may need. I guessing I kneed to know how high pressure the pump can put out, and how much I need for the Holley.

Right now the plan is to install a new needle and seat just in case it's damaged, and to put in a pressure regulator.

 

[dangerranger83]

Your carb. should be receving 4.5-9 psi of pressure.

 

[JoshT]

Ok, that gives me input pressure to the carb. Any body know what kind of pressure the fuel pump on one of these engines would be putting out?

 

[dangerranger83]

If your running the original machanical fuel pump it puts out 5-6.5 psi of pressure at 20 gallons per hour.

 

[JoshT]

Stock replacement pump. Guess I'll throw on one of these new needle and seat that I found to see what happens.

 

[JoshT]

It was the needle and seat valve, more precisely the O-ring on the outside of it had worn out. It's running fine now, well still needs tuning, but not pouring fuel.

 

[dangerranger83]

Great to hear you got it fixed.