2003 searay 240 sundeck with 5.0 MPI duo prop. Had it on mooring for the first time since purchasing it new, Always trailered. Well its been in water for about 3 months and today I went out and took wife and kids tubing and and at less than 1/2 throttle and higher it ran fine but I got no speed and alot of rumbling.. Could all the bottom crap cause this? Its got a decent amount of crap on outdrive and prop now since its been moored. By crap I mean Barnacles and other slime. I guess all that stuff on bottom can cause this? Yes it is painted but the drive ..Which looked like new 3 months ago now looks bad I wanna cry!