New info: I received my carb kit from Quadrajetpower.com, and began dismantling the carb. The good news is that the carb is clean inside, has already had the throttle shafts bushed and the well plugs epoxied, so it appears to be remanufactured, though not recently based on the outside grime. Remember the engine ran well, idled well, accelerated well, no issues other than being flooded at start, and blocking the choke open did not help.
What is troubling, is that even with less than 1/2 a tank of gas, fuel keeps dripping out of the fuel line where it went into the carb. (I've not yet completed the carb, so the line is open, save a piece of towel to keep trash out). Best as I can measure, the carb is above the fuel level, though that can be tricky to figure. I loosened the fuel cap to see if pressure had built up, but no sound of air whooshing, and the fuel keeps dripping.
I'm starting to wonder if either the vapor canister is flooded or the purge valve is bad, causing that, and indirectly flooding the engine after sitting overnight.
What do you all think?