I have a Twin Troller boat that has a Minn Kota 36lb thrust motor in each hull. The motors work great out of water but one of them works intermittently in water. Any advice as to what to check? I've sprayed the connectors with contact cleaner and made sure they are securely plugged in. Can these motors be rebuilt? Looking on the net I see a new motor is available from FreedomElectric Marine for $250. Thanks