Just recently bought a boat with a 1996 75 mercury outboard motor. It hadn't been used for a while when I bought it. It has only done no more than 40hrs work. The problem is whenever it revs over 3000rpm starts to knock and has no top end power if i hold flat the knocking stops but is not getting full revs or speed. It runs fine from 0 - 3000revs. I started motor and went to pull top spark plug cap off and it gave me a good boot before I got it off. Just touchng it was enough. The other two spark plug caps I could touch. I ave spent a lot of money thinking it was fuel problems but anything to do with fuel is fine. Any ideas would be greatly appreciated.
