I would see what style choke your rider has. Some have a fixed link and shaft and others have a wizard which is basically a little spring on top of the shaft that helps to control the choke. To access it, just remove the air box and have a look. When the top of the shaft cover breaks, they actually load up and can act just like you described.

Well thank you, but the choke is a fixed link and I was looking in there with the air cleaner off, partly to make sure the choke was open, (it was wide open) when I noticed gas spitting out of the carb at low rpm's off idle. The engine was very much at running temp at this point. My old rider has a good running B&S 20 horse twin, I'm thinking about frankensteining that onto this and being done with it. Thank you for the tip.

Leaking intake valve? Do a compression test? If you have a compressed air adapter for the spark plug hole - put on top dead center of compression stroke, put compressed air in it (50 - 90 psi) and see where it leaks out. Carb - bad intake valve, exhaust - bad exhaust valve, oil filler - bad rings, radiator - never mind:)

Is there further evidence of the float valve not holding IE fuel in the oil?It would be worthwhile to pull the flywheel and check the key.

All very good ideas and I will start running down this list this weekend, as the rest of the week is too busy with work and oh um work on the house. Thank you guys I do appreciate all of the great Ideas, and I will let you know what I find.