Originally Posted by bushyb
Thanks, I have had another look. It seems the problem could be the left carb, with everything disconnected and engine warm adjusting the mixture on that carb makes no effect to the idling. I can close the mixture screw all the way and there is no change. So I am assuming the must be a leak on that left carb. Would that be correct?
Most probably. Tear the carb down, rebuild it with all new parts. Have had the same problem on several carbs over the years. New o rings, jets, gaskets etc has always fixed it. The parts aren't expensive but it is a half day job and I've always done both carbs at the same time.