I've owned the boat for three weeks now and have used it 8 times so far with no problems, until this weekend. I started it up let it get warm, idled down and started out, I trimed down and hit full throttle but accomplished 2500 rpms. I tried nutral again and reved it up, this took there times. Then it was good all day. The next morning same thing but it took longer to fix its self. Then in that same morning the same thing and still doing it. It sounds as if it's muffeled. I took the plugs out they seem to have a thick black sludge on them but one on the top was not too bad.
