The bearing carrier,where the propeller fits in, on my Yamaha 9.9 outboard became corroded.It was stuck in there,and the bolts that keep it in were corroded away and needed to be heated to be removed. The motor has electric start and and an alternator that charges the battery. I don't let it sit in the water when the boat is at the mooring.The boatyard mechanic has replaced the part but has said nothing about what caused this corrosion.A friend said that current must be leaking into the motor and causing electrolysis. Any thoughts? How do you test for this How would you fix it? Thanks for your wisdom. Gerry, At Last 26,Falmouth,Me