alternator magnet chunks seen through casing.

[keithashleywaite]

I own a mercruiser 3.7 litre alpha one leg. I have replaced the gimble bearing and set off this morning for a nice boat drive, engine started ok, but when was hot would not start again untill cooled down for twenty minutes or so, i have had this problem for a while. I noticed my alternator power steering belt loose so tightened it up. started boat again and it seemed to be missing, stop boat and battery was flat. Then i noticed chunks of broken magnet through the holes in the alternator. Is this the problem? how hard is it to rectify this problem, is this a common fault with mercruser alternators. any advice appreciated. chhers keith