Back in 1953 carburators all vented externally so if the heat riser on that engine is stuck in the closed position the carb base is pretty hot. Shut off the engine and the fuel boils out thru the vent. Later carbs vented in the throat and flooded engines resulted in the same condition, these are one of the ways to drain the carb bowel. Also a high float level will result in siphoning of the fuel out of the bowel. With a needle and seat controlling the level it can't return to the tank thru the fuel pump. kotzy