Thanks for the diagnosis longrider, I pulled all the plugs and drained the offending float bowl and, interestingly, a whole bunch of gas leaked out the tank drain hose when the drain pin was pulled. Cranked the engine over, with the plugs out, and everything sounded and appeared normal. No gas came gushing out of the offending cylinder (drained through the vent hose maybe?) Drained the oil, no inndications of gas then installed brand new plugs, oil and filter. Put 4oz of Marvel Mystery oil in the tank, swished it around and fired it up. Kept an eye on it for short while as it idled, no rich smell, no gas out the pipe. Jumped on and went for a long ride. She ran beautifully!

I'm a happy camper. Will keep an eye on it over the next while before I go through the chore of pulling out the carbs. Thanks for the help. SC