we're talking about an '85 pickup with a 22R. I am confused as to how the idle speed screw works(I know what it does), and how to adjust the idle mixture. (see pics)




The SCREW in the inset pic is completely gone, but it doesn't affect my idle speed, or anything at all when I move the little arm up and down while revving it. I just want to make sure I'm not hurting the engine, and be sure that there isn't something else wrong that I can't find . . . it seems like there's supposed to be a spring there. And yes I know, I'm probably bad at explaining crap like this . . .

 

It looks like maybe that little arm is for the A/C idle up diaphram that hooks in the hole. If you do not have a/c then dont worry about it, I believe it has a little wire that holds it out of the way orginally.

 

hmm . . . one of the reasons I asked is that there are only two screws on the side of the carb that I could find, the one I'm referring to, and the on top right of the bigger picture . . .

 

I think the screw thats missing on your carb in the small picture is the fast idle screw. the idle screw is just below the red choke wire in the large picture.

 

ok, what's the diff between fast idle, and idle speed? is fast idle for the speed when the choke is on?

 

I think the fast idle is used when the engine is warming up, the regular idle screw is whats used to set the idle speed after your engine is warmed up, like when you have your truck just sitting there running.