i have a 17ft skiff with 2 livewells....i keep the boat on a lift. when i drop in the water and turn on livewell pump it does not get prime. the pump appears to be below the waterline at the impellar height. it seems to get air-bound? any suggestions. also, i would like to add a scoop to the outside of the hull, the type that fits over the existing thru hull intake. any precautions in mounting onto the ropelene hull..??