Hi Everyone... I rebuilt a 69 Q-Jet (7029202) and I'm having trouble getting it to idle smoothly. New float, epoxied the the two plugs underneath, throttle shafts seem fine. It acts like a Holley with a blown power valve. Stinking up the garage and acthing like it has a radical cam when all it has is a mild RV cam and origianl GM cast iron intake. I have not driven the car but the carb does seem responsive. The carb was running about the same when I got it which is why I rebuilt it. Must be something else going on...

One other thing I forgot to mention, I can turn the idle mixture screws all the way in and it still runs! Is the car supposed to do that?

Thanks!

I had the same problem as you mentioned.I'd spray some WD-40 around the base of the carb and see if you have a vacum leak....would explain why it still runs with the mixture screws in.But I belive your problems lies in the primary throttle shaft.I bought a shaft repair kit and the carb worked perfect from then on.

I'd bet a 6-pack the throttle shaft is your problem.

I'm having a similar problem with mine.... I just discovered the air horn is warped. I'm going to check the primary thorttle shaft too. Anyone know where to get a kit to change the shaft bushings?

If you can crank the idle screws all the way in and the RPMs never vary/drop, it sounds like the primary throttle plates are open too far. There is a screw on the passenger side of the carb on the primary plate rod to adjust this. I was taught that, with the carb off and looking at it from the bottom, that you should just be able to see the top of the two passages where the idle mixture screws sit when this is adjusted correctly. If you can see more of these passages, the primary plates are too open, and the carb acts the way you describe.

If you don't feel lke yanking the carb again and doing this on the bench top, I think you can turn the screw with the carb on the car. I'd turn the idle mixture screws most of the way in, and then adjust that plate (loosen screw, I believe) to close the plates until it almost shuts off from lack of flow. Then back the idle mixture screws out until it will run smooth again.