Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

Rich at idle

(1/2) > >>

highlander:
I have a carb that I rebuilt for my son's 1986 Suburban 350. It was originally equipped with an electronic carb, but the wiring has long since disappeared. I dug through my pile of Q-Jets and came up with a non-electronic carb for a 1985 Chevy 350. Anyway it idles rich enough that the mixture screws aren't doing anything. The vacuum is steady at 13.5, (we're at 5300' elevation), and if I use a small screwdriver I can feel that the power piston is fully seated. Can't detect any vacuum leaks and I did epoxy the plugs on the bottom of the bowl. I also rebushed the primary throttle shaft. I have been rebuilding these since the mid 70's and never ran into this problem before. The truck runs great otherwise. Any suggestions on where else to look for a possible fuel leak?

Cliff Ruggles:
What is the carburetor part number?

Did you install one of my kits in it?

highlander:
Carb #17085003 and unfortunately my kid brought me a Standard kit and new float. The only thing I thought questionable was that there wasn't any slack in the linkage for the secondaries. With the  curb idle screw backed out they appeared closed, but the linkage was tight in the forward part of the slot on the secondaries. And like I said, inserting a screwdriver above the power piston confirmed it was down all the way. Thanks for your help.

Cliff Ruggles:
That's where the problem starts, using over the counter generic parts.  Some later carburetors for the Chevy trucks require different gaskets or they will be pig rich at idle.

Could be incorrect gaskets, could be leaking at the N/S, and for sure the accl pump "blue" seal is a complete POS.

I get carbs in here all the time with those soft blue seals ripped, torn, or have swelled up and fell off the pump........Cliff

highlander:
The gaskets did match up with the ones that were in it. I guess if someone had previously rebuilt it using the wrong gasket that is a possibility. It does not load up and idles smooth, just rich enough that the mixture screws are ineffective. Do your kits include the specific gaskets or do they include a couple of choices? Which of your kits would you recommend?

Navigation

[0] Message Index

[#] Next page