'67 eville 429 Staying on fast idle after warm up

[Julien Abrahams]

Hello everybody,

The other day I took my '67 Deville for a drive for the first tim in a month. I noticed that after the car had warmed up, it stayed at fast idle (instead of going to base idle). So I removed the air filter and when I checked, I noticed the choke valve was completely open and the choke had pulled the intermediate choke lever completely down. Normally this allows the fast idle cam to rotate when the throttle valves are opened so that the cam follower drops off the second step which results in the engine running at slow or what I like to call base idle.
I was wondering why it remained at fast idle, although it had completely warmed up.
Because the fast idle was really high (in my opinion) I turned the fast idle screw out by about half a turn to bring the fast idle somewhat down.
Is something binding (or needs to be lubricated)? I've had the car for 5 year now, and this is the first time it has happened.
I believe that I understand most of how the Quadrajet choke system works, but I'm kind of scratching my head on this one. Help is appreciated.

Julien.

[Coupe Deville]

With the air cleaner off, can you push the fast idle cam down with your finger, and does it stay there by it's self? I had a similar problem with the fast idle cam hanging up on the first step of the cam on my quadrajet on my 472 a few years ago. A little bit of silicone spray made the problem go away. When you think about it, gravity is the only thing that's going to pull the fast idle cam down. So if the linkage gets sticky, this can happen.
Let us know.

-Gavin

[Jeff Moffo]

Same thing occurred on my 1976. I actually took the choke element out. Seemed also that the choke was set too rich. I reset the choke and shot the fast idle linkage with carb cleaner and then a quick shot of WD 40.

Good luck.
Jeff

[Scot Minesinger]

agree with Gavin

["Cadillac Kid" Greg Surfas 15364]

67 has a divorced choke.  Problem most likely solved as Gavin suggests.
Greg Surfas

[Julien Abrahams]

Thanks for the replies guys! You're right. I can push the cam down by hand and it will stay there. If it jumps back, then usually the fast idle screw is too far out.
Now I think about it, gravity is the only thing that will pull the fast idle cam down as the spring tension is only there when it is pushed upwards by the choke link. I will try as you suggested as soon as I get the chance.
I will keep you informed.

[Julien Abrahams]

Update:
A bit of silicon spray appears to have done the trick. Thanks for the tips.

[Jon S]

Update:
A bit of silicon spray appears to have done the trick. Thanks for the tips.

Although silicon spray will fix it in the short term, it is best to spray the linkage with carburetor cleaner and keep the linkage totally dry and gum free.