When I first picked up the amphib Beaver for Kodiak, it hadn't been in water for a year or so.....those floats leaked like sieves. I rigged up a small 12 V pump with a plastic hose that fit the pump outs. After a week in the water, the floats gradually sealed up, with just a few minor leaks. According to JJ Frey, the Zinc Chromate paste tapes that EDO used between laps actually absorbed some water, helping to seal the floats. After Maintenance sealed up the few remaining leaks, life was good and the pump wasn't needed.
If you really NEED a powered pump for your floats, get them out of the water and seal them up. We've been over a really easy procedure on this board a couple times. Seal them and all you'll get is a few squirts out of each compartment.
MTV