I have a Johnson 175 faststrike 1992.  Boat cranks and runs good at idle, but takes forever to plain off and then will only reach about 30mph and go about a mile and it will drop off back to just and idle.  What can my problem be?

Also I took both lines off the fuel pump and turned the key gas shoots out 3-4 feet on both sides.  I took the plugs out and they almost smell burnt.  By the way this is a brand new power head!

Sounds like a timing issue to me.