If your slide is sticking, and sometimes they do, you have two possible problems, the carb top is screwed on too tight, or the slide is sticking. If it is the latter, you can sand it with some 400 grit paper and a little light oil like WD-40 to get it to fit.
If the twist itself is sticking, you can trim it with an exacto knife, or sand the offending parts a bit as well.