Re: Carb/High RPM/Frank
Believe it or not, with all the junk engines I have bought and salvaged and with all my running engines, I have never bought a carb rebuild kit.
I suppose I have been lucky enough that cleaning was sufficient. I have had a couple that were corroded beyond repair and they were thrown out. But on the whole, a good cleaning and adjusting was all that was necessary. I also found that WD40 is an excellent cleaner and removes most varnish almost immediately. Pipe cleaners and WD used carefully will clean some of the metered orifices and the thin brass idle circuit dip tube. I can't remember ever finding a saturated float that needed to be replaced. I do, however find a lot that need to be adjusted to correct height.
The only gaskets you will need are (possibly) the cork bowl gasket, and the two gaskets that seal the bottom nut inside and out. If you replace the inlet needle and/or seat, then there is a copper gasket for the seat which you will need.
There again, I have so many carbs--probably around a hundred--that I just steal parts from one I am not using and, most times I re-use the cork gasket. It usually has a well defined groove from the bowl but will seal adequately if not torn or cracked. Simply bend out the bowl bottom (with your fingers) a little so that when it is attached it still puts some pressure against the gasket.
Thinking further on your carb problem, if you needed to tap it to get the engine to slow down, It could be varnish build up on the butterfly shaft. BUT: it could also be binding of the tower shaft or ball links, not allowing the cable to pull back the linkage to closed throttle. You need to check there too. and be certain the cable itself retracts fully with no binding.
