I agree with above, probably water
contamination. Bad news if it is. Salt water
in the bearings can ruin them so you want to change it out and then run it for an hour and change again, and again until no sign of water. It might be an O-ring, or it could be the shaft seal
. Might be wise to have it checked out if you don't feel confident to do it yourself before going in the water. Good luck.