When you say the black cover I think you are talking about the bottom half of the round air cleaner container. Is that correct? If so, then gas should not squirt upwards. That is strange.

Fintails are notorious for having the gas drain out of the carbs (backwards) and needing to be cranked for a long time. But if you are getting gas squirts from the accelerator pump then the carbs are not empty. Loose distributor center wire? Secret kill switch?

cheers
Scott