Truck Idling Very Fast When Started and Engine Cold - Any Ideas?

[jb3t]

I have a 1978 C10 and when I start the truck, it idles very fast. I don't have the tachometer so I can't tell how fast but it's significant. Once I put her in drive and start going down the street, when I get to the stop sign, I can still feel the engine revving and have to hold the break extra hard. However, if I drive for a while, it idles at regular speed.

Short story... When the engine is cold (under 15 min of driving), it idles very fast. Seemingly, after engine is warm, it idles normal.

Anyone see this before? I'm no carb guy but I think it's the a fast idle problem. I'm also wondering if there could be a vacuum leak somewhere but I am unsure what to check. Not sure if anything else plays into this like a fuel filter.

Any guidance would be appreciated.

Thanks a lot.

[geezer#99]

Look here!
Simply turn down your high idle and maybe lean down your choke.
http://www.vetteprojects.com/kstyer/quadrajet_3.htm

[jb3t]

Thanks man... Going to check for leaks first I think. If none, then I'll check the adjustments. It could actually be a sticky arm or a vacuum leak like in your first picture.

[jb3t]

To add to the story, the choke is about 30% open after I start it up. If I'm looking from the passenger side, it's open to about 10 o'clock. It I fully open to 12 oclock, she settles down.

Lastly... The fan is really cranking as well.