Hey G the idle mix screw only affect your carb at idle has no real affect after idle your rich condition is most likely a dirty airfilter or if you have been moding your carb the main is to large.Try a clean filter and new plug if still rich clean the carb.To set your idle turn mix screw in all the way then out while running untill you get the highest idle than back the screw off 1/4 turn.Hope that does it.1 1/2 turns are close to factory,but your envirnment can make this change,so your setting whats best for you where your at right now.
