yep the rpm's pickup as the float empitys an for the rich mixture are you running a stock airfilter? and did you spray the carb or dip it cuz the airway by the air screw likes to get gummed up I also suggest filling the tank half way and scrubbing it with a bottle brush then draining the fuel by removeing the petcock and filtering it doing this a few tiimes till it looks clean (its easyer then taking it off and doin the nuts and bolts thing) find a friend with a drum of carb dip and let it soak for 24 hours or so (take off everything plastec or rubber remove the air screw idle screw and float first ) then flush it out with water and compressed air. I did this for my qt it had the same problems sat for 20 years, now it runs like a champ.