hope you guys dont mind that ive got a pontiac question but everybody here always seems willing to help somebody out unlike other (pontiac) forums. so here goes my question. Ive got a 2GC on my 64 pontiac 389. ive rebuilt it and adjusted everything to make it run very good. the problem is that after the car gets up to about 180*F i see a considerable drop in idle RPMs. it idles at about 800rpm in gear when relativly cold but as soon as it the temp comes up its running at about 400-500 rpm and seems to want to die. im out of ideas with this car. the hunt for a 4-barrel begins. thanks, Joel
There are 2 idle screws. One is for high idle - when your choke is engaged. This screw is on the passenger side of the carb. The other is on the driver side with the throttle linkage. This is the one you want to turn up.
this 2GC only has an idle screw on the drivers side, its the original from 64. the choke housing is round and attaches to the throttle body. theres only one idle screw on it. im almost 100% sure.
This is one of the shortcomings of having this carb. If you look at the places where the screw comes into contact with the resting surfaces, the problem is obvious. The steps are rather large, especially the last one. Is there a solenoid used on the A/C equipped unit that you use. The idea would be to connect the solenoid to the ignition switch, which raises the throttle linkage slightly. You could set the fast idle where it worked the best and use the solenoid for the slow idle. Just an idea. Food for thought...if the engine is cammed for a two barrel, the four barrel may be a disappointment. They are cammed slightly differently. Ray
One other possibility would be to file down the highest step of the fast idle cam, or bending the link so that even with the choke completely closed, the screw rested on the second step. This last will make the engine idle drop faster as the engine warms, but it is food for thought. The purpose from the factory was that the choke adjustments were a little less critical, but for those of us who understand its operation, we adjust the choke to provide the engine what it needs, which makes the idle excessive...Ray Ray
the car is a factory non a/c car so i couldnt use the selonoid. i would rather have a 4-barrel just to get away from this carb. im not looking for much of a power gain seeing as how the car is literally a boat and it wouldnt surprise me if it was well over 6,000lbs. this carb has given me such a headache i just want to throw it away. thanks for all the help. Joel
