Add a leaking bowl in to this, and I could see a dry carb in a few days.
add a Rochester B name to the carb and you could see a dry one overnight

mo2 - the 'pressure' is on the needle, when the engine is off there's no longer pressure - the float cannot "let the needle move", it controls it's position, as the gas in the bowl evaporates, the float sinks and will open the needle inlet - but no fuel will exit .... going dry over time is very common with that carb
Bill