Well, I attempted to adjust my idle mixture a couple days ago. Found the brass plug, no problem, tiny hole already in it, used a screw (two, actually, because I managed to pop the head off the first one before it got a good bite on the plug) and a pair of vise-grips, came out with a little bit of effort, but not too difficult. Then I...screwed up. Either I used too much force trying to get the screw to back out, or, possibly I drove the plug pulling screw too far in and damaged the mixture screw . Anyway, initially thought that maybe if I turned it in it would loosen it up. So, now my idle mixture screw is 0 turns out so my low end lacks oomph, and I need to get a screw extractor and a replacement screw or need to find some other solution to remove and replace damaged screw.

So, now that you've heard the story, a few questions. How badly could I screw the carb up if I screw up with the screw extractor? If the answer is "horribly" or worse, would I be better off trying to replace the entire carb, or just any damaged parts? Am I being too paranoid?

It can be accomplish as Babbalou said but you have to take your time in doing it and go in slowly. Just remember that you are working with soft metals so work slowly and carefully. Good luck dude. Oh remember to [glow=red,2,300]center punch the screw [/glow] before drilling