Motor is 2003 Suzuki DT 150. Posted this spring about water in lower port cylinder. Dealer did leak test and came back fine back in May. He ended up replacing port exhaust cover gasket saying part of the gasket was pushed in and probably caused the leakage. Boat ran better but still produced a lot of white smoke at idle and high idle i.e. above 3500 rpm. Boat performance has went slowly down hill since then. Checked plugs tonight since it was sluggish all week at the lake and found the same white-grey coating on lower port plug like there was this spring. All other plugs are clean. At WOT it seems to surge every so often kinda like that cly. is cutting in and out. I'm sure that gaskets are supposed to last more than a summer. Any ideas or suggestions to look at before I take it back to the dealer? If it's going to be any easy fix, I'd much rather fish than have my boat sitting at the dealer.