offsetfactor

Ok i got a used carb for free, person said it needed a diaghram. so i replaced it.


i just did a tbi to carb swap. and the car starts and is leaking fuel and it looks to be coming from where the rod goes through for the secondaries

i didnt adjust my mallory fuel pressure regulator, i just put it on. did pressure break the carb and cause it to leak? or should i not have to adjust the regulator out of the box? I mean its probably just the carb right?

Batass

No pressure gauge? Should be set around 6. When too much pressure goes in it just overcomes the floats and keeps the needle/seat open, pushing fuel through your jets into your intake. I had that experience yesterday. A beautiful bubbling display of vaporized gasoline. Rather dangerous....

Are you talking about the rod for the pump? That would be a bad pump diaphram. Maybe something else in that area. Been a while since ive been in there but i think theres a check ball and wire that can wear out too.

Also tbi requires i think 20 psi. Way too much for a carb. Youll overcome the floats at about 15 I think.

MariahFan

Hmm...

The Qjet is infamous for the throttle shaft bushings leaking (primaries), but I haven't personally seen this problem on the secondaries, but I suppose this is possible? If so, you can get it fixed, but it's probably a better investment to buy a new carb or find a used one with a good baseplate and swap it out. My original Qjet started dumping all sorts of fuel out of the primary throttle bushings (the bronze material wears out), not pretty seeing all the fuel sloshing around on the intake.

I don't think too much pressure will "break" a Qjet, just create a scary situation like Batass said.

Batass

Oh, I guess hes talking about the butterfly rod. Not sure how you would fix that on a q-jet. My holley did the same thing when i put 15 psi of boost to it.