Re: Mercruiser Exhaust hose help !!!
The exhaust "hose" you're talking about is called an exhaust bellows. It's not having any effect on your boat, it's full of water anyway any time your boat is in the water. It connects directly to the center of your prop where the exhaust gases come out.
Replace it, take it all the way off, or replace it with an exhaust tube (rubber tube that only connects to the boat end), something else is wrong with your boat. You may want to look at your u-joint bellows, which is the big bellows just above the exhaust bellows, and your shift cable bellows, which is the little bellows on the right if you're facing forward in the boat. Either one of those WILL let water into your baot, and if the exhaust bellows is bad, they probably are too.
Do a compression check on the engine to determine if there isn't something basically wrong with it. 470's are notorious for blowing head gaskets if overheated, and overheating will also destroy an exhaust bellows as you've described.
