High idle

[Fingers]

So, finally got this truck home. It starts really well, but idles super high. The choke is all the way open, I backed the throttle adjustment screw all the way back, but no dice. I took this picture of the carb since I still don't know a lot about them yet. Seems like something is missing?

[Law Dog]

later model the same? I can get you more pics if you need more.

[FMS88]

So, finally got this truck home. It starts really well, but idles super high. The choke is all the way open, I backed the throttle adjustment screw all the way back, but no dice. I took this picture of the carb since I still don't know a lot about them yet. Seems like something is missing?

I don't see anything missing if your truck has an auto trans. Post pics of the other sides of the carb. They'll be more informative than that of the right side. Check the fast idle adjustment screw and cam, and the kick down cable adjustment or connection to the throttle linkage. Removing the detritus that's accumulated around the accelerator cable and lubricating the throttle linkage might also help.
Unfortunately the carbs with electric chokes in Law Dog's pic differ from yours and won't fit an '86 and earlier. Yours has a water choke which might be the cause of the high idle, but my experience with the water choke models is very limited. Those with Gen1 trucks should be able to help.

[xboxrox]

Hello Fingers ~ there seems to be much dirt grass or rats nest around the carb & throttle cable ~ suggest cleaning things up in the engine bay ~ the idle screw is hard to reach due to the choke cover tamper plate ~ ignition timing if off (too advanced?) can cause high idle ~ clean up & make sure it's the idle screw you're turning

Good Luck

[geezer101]

Also check your throttle cable adjustment. If the cable has no slack at all on it, someone may have been messing with it. And as xbox has suggested, check your timing. If it's waaay advanced it'll idle high. It sounds like someone has run into a fault with it and tried to adjust it, subsequently causing another issue. These carbies are no fun to mess with, especially for the uninitiated. Pick out all the crap built around the throttle linkages and choke assy etc as everyone has recommended and give it a hose down with a can of carb cleaner. Let us know how it goes