I have recently rebuilt 2 quadrajets, following a manual, and they both are having the same problem:

They both idle high (1600-2000 rpm). On the first one, I added a second throttle return spring (seems to help it quite a bit). The second, it didn't help much. Looking at the carb, the throttle lever does not return all the way to contact the idle screw (or the "fast idle solenoid"). I can pull it back all the way to bring the idle down, but it "springs" right back.

If I pull the fast idle cam forward towards the front of the car to the point where the choke plate opens all the way, the throttle lever returns all the way.

Am I installing the cams/linkages behind the choke incorrectly or something? Has anyone found a good video on installing those in the correct order and orientation? tried searching with little luck.

Please let me know if any of you have experienced this and had any luck with a remedy!!!! I'm stuck!!

 

Sounds like the fast idle cam adjustment screw is jacked in too far, try backing it out and see if your idle comes down.

It likely with the carbs being messed up (needing rebuilt) someone jacked the high idle screw in to get satisfactory cold idle speed.....

 

I will check that tonight. I was also told to remove the gasket that is made to go between the electric choke thermostat and housing. Is this common practice?

 

I had a similar problem and took it to a shop. I think they found that the base gasket(between carb and manifold) was interfering with the secondary throttle blade. And believe me, I took the carb off a few times.

 

There are numerous intermediate gaskets that are used on Rochesters. Make sure you use the proper ones or this could happen. Also, make sure your rebuild kit if for your serial number carb.

 

The fast idle screw below the choke took care of the issue. Just had to back it out a little, enough for the cam to drop!! Thanks for the help guys!!!

 

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