Well there you have it, it seems the float valve is not shutting off.
additionally, judging by the burned off paint at the choke-well,Ima guessing, your heat crossover is not working, or is majorly full of carbon, or the Heat-Riser valve is frozen, or the exhaust is restricted.
The latter may be the principle cause of the former, but may not be the whole of it..
Yes it is possible for the fuel to boil in the float bowl and bubble over into the throttle bores. The lightest gas molecules start to boil at 95*F. Your first defense against that is an insulating gasket between the carb and intake.
If you have an IR gun, shoot the carb in several places,next to the intake, and also shoot the chokewell, looking for the highest temps.
The only way to clean out the heat crossover is to remove the intake, flip it over, remove the rivets holding the splash shield on, and chisel out the crud. Then chisel out the actual crossover as well.
Your engine craves cold air from somewhere else than under the hood. Underhood air could be two or three,or more, times as hot as what is hitting the rad.
