I have a 2005 Yamaha FX Cruiser HO. Just dropped it in the lake to start the season. At idle speed it has a low rumble sound that it didn't have before. when accelerating it feels like it is slipping in the water and running at high rpm until it get to about 17 mph or so. then it feels like it "catches" in the water and hauls ass as usual. still tops out at about 52 mph. i looked up at the impeller and it looks ok from the outside. intake is clean. my stepson told me it did the same thing at the end of last season when he pulled it out of the water. i winterized it and put it away until today. any ideas? thanks for the help.