There are times with a dirty carb I have revved the engine holding the throttle open all the way open as I closed the choke almost killed it with the choke by hand.
This is what it needed.
I put on a heavy leather glove, started it up then put my hand over the top of the carb trying to choke it off as much as possible.
This settled it down to "normal" levels
Nice smooth idle.
But, still has really high idle. I mean soon as she fires up she is at 3,000-4,000 RPM
now I wonder if I have leaks around my intake/heads???