vibration

[rntim1]

Have a '85 Seacraft MA with a '85 merc. 200 hp. When I minimum speed down the canal to hit open water, I seem to get motor vibration but when I open it up on the open water, it chills out and so smooth. Also, get a lot of water influx thru the spunners (hope thats right term) but drains all out no prob. when running out on the water. Even got some water running into the splashwell--my weight of all of 150 pds does this! Motor is original and all was well maintained prior to me buying her. Transom is rock solid and prop is not damaged. Any thoughts? Thanks.