Adam, not knowing what carb you have I must speak in general.If fuel can make it from the bowl into the throat of the carb some will evaporate and the rest will pass into the manifold/cylinders/crankcase.When this condition exists you would be experiencing hard restart when warm/hot and the idle would probably be bad and fuel would be seen dripping into the throat of the carb at idle or after shutdown.If you could stand to keep an engine working in this condition the crankcase would likely see a slow rise in level but if it were worked hard most of the fuel would boil off and be vented to atmosphere.Most carbs are designed so fuel cannot transfer by gravity from the bowl without unusual circumstances-one exception is the quadrajet and it's derivitives.The fuel pump is your most likely cause and this is a common failure.The pump most times has a telltale hole in the body under the diaphragm near the mounting flange to indicate leakage.The hole could be plugged w/grease and dirt and I have seen some pumps without the hole.

Bob Taylor