Ok I took the boat out this weekend for the first time after a long winter. I got back today and was cleaning the boat when I noticed black sludge inside the prop and around the carter pin area. It was allot. I curious what would cause that? I'm thinking it to be the cocktail mixure that I did to the enigines when I winterized. I mixed gas, sta bil and fogging oil in a can and ran the enigines with this.