the two brass bars in the carb throat should be about 1/16th of an inch from each other when the throttle is at HALF throttle. a friend of mine had one, and we could not get it to run right.. and i can tune just about any motor, (so i thought) but i couldnt get that one, so we took it to the lhs and the german local went to the shop and 20 seconds later handed us back the motor and said try it now, and that is the only thing he did. ( it will be the low speed needle) you need to set.