When I start the car in the morning I pump once to set the choke and turn the key. Instantly the car fires up to around 2000rpm. It will stay there until it is sufficiently warmed up and then I very lightly tap the gas and it drops to idle speed. Is my fast idle too high?
The fast idle is controlled by a stepped cam that rotates with the choke. There is a screw that contacts the steps of the cam, and that is the adjustment. The screw is on the passenger side of the carburetor, and it is somewhat buried in the linkage, you need to look for it. Adjustment numbers vary by year, but they all involve a warm engine, in gear, the adjustment screw on the low step of the cam. In 70, it is adjusted to 620 RPM. In 72, the number is 700 RPM Auto Trans, 920 RPM for the 455. When the engine is cold, the choke rotates the cam to the high step, and fast idle speed is correct.
Ive known what it looked like but I guess I never took the time to find out how to adjust itou:. I never realized there are different steps on the fast idle cam. Does it actually go through all these progressively until the car is warmed up and the choke is closed? Every time I warm up my car I always wonder why it fast idles so high. Adding to my list of projects finally I'll have something to do this weekend:beer Carburated cars are becoming less and less of a strange concept thanks to you guys!
Let me ask you something. Do you own a Buick Chassis manual for your year? It should have been the very first thing you bought after the car. It amazes me that guys will spend on all kinds of things for their car, but neglect the most important. There is no excuse. Originals are available on E Bay, in reproduced form, and even on CD ROM. The answer to your original question is in the Chassis Manual, along with alot more.
I use the manuals on Team Buick:TU: Sometimes I just forgot to look there but I also prefer to ask others on some topics just to see if there are any procedures or tricks I would miss by simply reading the chassis manual. I should pick up a 72 manual though as team buick only has the 71 edition and it is tedius to go through different sections. Thank you for the link!
Just an update, I determined the reason my fast idle was so high was because I ran my car without an idle solenoid. It is my understanding that when you do this you are required to set the idle with the idle set screw in order to maintain proper idle rpm. When you do this you also raise the fast idle since the fast idle adjustment is the idle set screw. When the idle solenoid is installed you normally adjust the idle through the solenoid. Correct me if I am wrong but thats just what I came up with:Smarty:
