I bought some seachoice livewell pumps, which are suppose to be thru-hull, but I already had thru-hull fittings and figured I could set it up inline. Well they will not pump water. Figured it was because I set it up inline. Well I took them off and put the pump directly into a bucket of water, still wont pump. Only way it will pump is if I completely submerge the bottom half of the pump. So it obviously isnt sealed or something.. Or maybe these are just cheap. Anyone have any ideas?