Do yourself a favor. Get a piece of paper and a pencil, and write down how many 1/4 turns off you turn the idle screw. That way you don't get yourself lost in where you're at with it.

Give it a quarter turn, then test it, nuther, test it, etc. until your symptoms stop.

Naw, it just won't start. <img src="/forums/images/graemlins/wink.gif" alt="" />

Also make sure that o-ring on the idle screw isn't rotted. That usually leads to it being erratic as a symptom, but doesn't hurt make sure it's okay.

You can always rent a tach from a part store too, if it's that much of a concern.