This is what PWC manufactures don't want you to know! I've often wondered why all the manufactures Yamaha, Seadoo, Kawasaki, Polaris, etc.. do not install a valve to shut off the cooling water supply to the engine. What I heard is shocking. Imaging this, You are a proud new owner of your PWC and while riding the engine suddenly dies. Luckily you find someone who can tow you back to your trailer. You take the ski to the dealer, since it's under warranty, right? Next day you get a call from the dealer saying sorry you're not covered under the warranty since the engine is full of water and water intrusion is not covered under warranty. They are looking at you like you sunk it and now you want them to fix it for free.. The Facts. The water actually flooded your engine after the failure and only because you were towing it. You were told when you bought the ski that you need to have it running while flushing the engine on a hose. Well the same is true while towing. While towing water is forced up though the cooling passages of the engine and dumped into the exhaust where normally the exhaust pressure blows the water out the exhaust. Without the engine running the water continues to build up in the exhaust until it completely fills the exhaust and flows up the exhaust pipe, into the exhaust manifold and floods the engine completely full of water. The Solution. Install a WaveEater Tow Valve on the incoming water line.