I've noticed that some pumps have that problem and others do not. Doesn't the pump shut off when the nozzle pressure gets too low?
Anyway, it takes a LITTLE longer to pump when it's like that but an hour is a bit ridiculous. When this happens again, either try a different pump or squeeze the handle only enough to get the gas moving. Don't try to pull it all the way or even enough to lock it at the lowest setting.
