How do I adjust my Qaudrajet Carburetor for my '82 Firebird with a 305?

Question

I'm only looking for a basic adjustment...I don't know anything about carbs so I can't do that advanced stuff. I just need to know how to adjust the 2 screws in the front which I am guessing controls how rich or lean the mixture is. I'm sure I only need a screwdriver, but maybe I need something else. If you have any other basic tips for me that will help it run better, please let me know. Thanks a lot guys.

Answer 1

Those are supposed to be sealed, but I suppose someone broke the caps off. They control the mixture strength on the primaries. The right way to adjust them is to tune everything else up first: distributor, wires, plugs, idle RPM, all perfect. Then use an exhaust analyzer to get the air mixture to 14.7:1 by adjusting the two screws equally, a little at a time. If the idle speed has changed, adjust and do it again until everything converges.

Before pollution control, we'd adjust them by ear. Usually this meant turning them in until they seated (gently), then backing out each screw two and a half turns. Then, one at a time, you would adjust a screw until RPM was maximized, then back it down to the "lean roll" position...where the engine just starts running rough. Then turn it back up about half a turn, to where it felt smooth and sounded "right".

Answer 2

run both screws in until you feel them just bottom out and then back each one out 11/2 turns and start the car, either using a vaccum gauge or a tachometer adjust each screw for the highest reading you can get on each one and then there is a screw on the linkage that controls your idle, set it so your car idles around 1,000 rpm. and your finished.

Answer 3

run both jets in,just until they seat(not too much,or you will mess up the seat)now run each 1 out about 1/4 turns and start your car,now run each 1 out 1/4 turn until you reach the best idle.

Answer 4

hi how are you doing?