i know this is an old thread, but take a look at the exhaust hoses that make the connection between your baffle/resonator where it "t's" into the horizontal hoses in the transom. i recently had a problem where i seemed to only be getting water inside the boat when the engines were running. this turned out to be my issue. that hose is nla from the dealer if you need to replace it. however, Gates sells model 21492 radiator hose. 2 1/2" on the top molded down to 2". i just replaced one of mine this afternoon in fact.