I don't think that it takes much to lock up a 12 volt DC motor. There were probably a few rust spots sticking that got polished away once you got it spinning. If it was mine I would just use it until there are problems. If it's not making noise and it's pumping how would a new one be better? They're not really precision instruments, they just push as much fuel as they can according to how much voltage they see. The regulator controls the pressure. Should be fine, I'd guess.