Got my first boat this week. A 1999 crestliner pontoon. It has a 40hp force by mercury on it. So first time out on water it was running little rough had a slight studder. So opened cover up and checked plugs. Bottom plug was little milky white. Cleaned and reinstalled. But also noticed water in the bottom of cowl and oil residue in there. So started it up and seems water and exhaust coming into cowl. Also noticed water coming from coming from between cowl and lower unit running down driveshaft housing. Previous owner said shop told him exhaust seal was bad and need to remove lower to fix. Got great deal on boat now to try figure out where to start. Any help would be awesom