91 cobra stearn drive

I used our 91 fourwinns last w

I used our 91 fourwinns last week no problems. Lowered the outdrive today and gearoil started pouring out of the prop.And there is some sort of melted thick rubber seal stuck inside the prop.A mechanic told me that it was the melted exhaust flapper that keeps the water from flowing backwards up the exhaust. Has anyone else ever seen or heard of this because it sounds like it's goin to cost a fortune to fix.

"It could very well be althoug

"It could very well be although I've never seen one get that far down through the system. I would be concerned what caused it to melt like that. Depending if you have a 4 cyl or a v? you will have one or 2 of these exhaust flappers in the exhaust pipe. When you start the engine there is always water flowing out the exhaust, the t-stat just controls the flow through the engine itself. For the flapper to melt you basically have to be running with no water, either out of the water on a trailer with no hose/muffs or in the water with a water pump failure in the drive. Either way it has to get very hot in the exhaust for them to melt. For the oil coming out of the prop area that could be just a prop shaft seal. There are 2 seals back to back down there, one is to keep water out of the oil and the other is to keep oil in there. Common problem down there is to pick up some fishing line which cuts right through the seals. You'll want to pull the lower oil drain and check for water in the oil as well. See the attached pic of a 4 cylinder and look at item 81 right side middle, this is the flapper (if you have a V? then you will have 2) Both problems should be reasonably easy for your mechanic to fix and not too expensive. By the way that melted flapper could have bee a result of a problem from long ago too that has just worked it's way down and possibly has already been replaced? Don't know the history behind the boat.

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"I burned that flapper when I

"I burned that flapper when I had a problem with the stern drive water pump and no water was mixing with the exhaust gases. I learned the hard way to always check to see if i have water flowing - either by visual inspection at the transom or sometimes by just grabbing the water hose that runs above my spark plugs. if it feels cold and does not collapse with a light squeeze, there's water.

BTW - the flapper is not hard to install. The only tricky part is to not lose the pivot pin down the exhaust tube. That part is kind of tricky on my FW Freedom, as it's basically a blind install."

"yes mine is a 3.0 130hp. I ha

"yes mine is a 3.0 130hp. I have always had a good source of water, muffs or the lakes and no overheating problems.We have had no problems with it till now.I'm starting to think that this happened before we bought the boat which was three years ago. Thank you for your input."