Unless someone has been dinking with it a simple rebuild and new floats should fix his problem. Don't forget to properly adjust the floats and in general verify/tweak all the adjustments called out in the rebuild kit, as needed of course, if it's in spec don't tweak it. You shouldn't have to fool with the jetting, it's not really adjustable without replacing the jets with different sized ones, so inother words they don;t go oult of adjustment or wear.
Another possibility is that the choke is not opening up, which would make it run rich.
Steve
