Changed thread title since I’m convinced my issue is in the carb.
The intake manifold is not exactly dry but there is no pooling. I stuck the corner of a paper towel in and had a tiny bit of damp on the very tip.
Removed needle and seat. They look clean but I sprayed them and the passage with carb cleaner and blew them out with compressed air.
I mentioned I could see some dribbling into the secondary venturi and some occasional splashes down onto the throttle plate. I do think this is likely the root of the surging behavior. I’m not knowledgeable enough to know if there should be any fuel at all through that location at idle, but I have to keep the rpm high enough for the engine to keep running.
The drill bit trick may allow me to get a good float height measurement. I’ll try it. However it appears the float is above spec and if so the bowl fuel level should be below the secondary venturi outlet.
