I was driving along today at full speed when my boat started reveing high and I stoped. When I went to take off, my moter would rev high. I would only go about 2 mph. I looked for a cotter pin but I could not find one. When I pulled the prop off, on the inside I found a seal. I was able to pull it off with my fingers. I don't think I should have been able to do this, but I did. Does this sound like a bad prop. or something else. I have a MERC. 500 1963. 