There is a cable that leads to the throttle. It has a screw type adjuster on it and when I tighten it the idle speed increases. How is this different than the idle screw on the engine?

 

dude if your asking this kind of question you probably shouldnt do any of your own work............

 

Hmm... I'm not quite sure what you are talking about. There IS a cable that goes to the throttle, and there should only be one. If so, then that cable goes to your carb. There are two adjusters that I'm thinking about. One is in front of the housing, a philips screw, and that is for adjusting how far the throttle can go. If you have kids and only want them to go so fast, etc. The other is where the cable butts up to the throttle housing. This adjusts the tension of the cable. Say if you have to much play, it tightens it, etc. This is probably what you are talking about. As you tighten it, it pulls in the cable, which, if you tighten it too much, will act like you are giving the quad gas. It's not really adjusting the idle speed, just giving the quad more gas then idle. The idle screw on the carb does what it says, adjusts the idle. Turn it in or out to adjust the idle speed.