i have a 700cc yamaha fx1 stand up ski, every time i put it in the water, or even just flushing it out at home the exhaust fills up with water and the ski loses all power, but when its completely dry runs fine. There is more water coming out the exhaust than the jet. Any ideas why the exhaust is filling up? i have had all the hoses off and they are all clear and all the exhaust joints are sealed and tight. any help would be appreciated. thanks.