I want to upgrade my bilge pump to a Rule 1500. The current pump is extremely hard to get at but using a mirror & flashlight I can see it's a Mayfair. The problem I have.....I can't seem to figure out how it's mounted in there and can't get it out. I can reach it with one hand and can turn it in either direction but the base and all turns together. Anyone out there know how the Mayfair pump fits to the base? The Rule snaps into the base. Thanks in advance for your help.<br />Kingfisher