Question about rubber exhaust flaps

[scottyfum]

Hi, i have an 2001 Mastercraft X-Star and I have a question. This might be a stupid one but what are the purposes of the ruber exhaust flaps? I am a new owner of this boat and I assume they keep the noise levels down, but I may be wrong. Any input would be greatly appreciated. Thanks. Scott

[1redTA]

I believe they help keep water out of the exhaust

[east tx skier]

Originally Posted by 1redTA

I believe they help keep water out of the exhaust

This is correct. More specifically, they are to keep water from forcefully entering the exhaust, i.e., they are not designed to seal tightly.

[scottyfum]

I noticed they do not seal tight so is there that much of a down side if they are removed. The reason why I am asking because mine are ripped and I want to go out ridding tomorow. I can't think of any way this can damage the engine so I removed them until I get my new ones in or make new ones. Thanks. Scott

[broncotw]

I would be hesitant to run my boat without the exhaust flappers on.... I think they are there for a reason and if they were not needed MC would not install them in the first place..... Just my thoughts bro....

[thatsmrmastercraft]

Originally Posted by scottyfum

I noticed they do not seal tight so is there that much of a down side if they are removed. The reason why I am asking because mine are ripped and I want to go out ridding tomorow. I can't think of any way this can damage the engine so I removed them until I get my new ones in or make new ones. Thanks. Scott

Without them there, you could get a surge of water up through the exhaust and possibly get as far as your engine. Worst case scenario would be to hydro-lock your engine. Get out a roll of duct tape and make them work. Then get some from your dealer or get them from skidim.

[east tx skier]

Do not remove them.

[SJ02]

I have new ones if anyone needs them. Send me a p.m.

[paco_06]

I did this exact thing to my last boat. Backed in the water, hit the key, engine locked up!

Backed in the water the same ramp, same speed, same everything as a hundred times before. Ruined my day, and also ruined my night as I pulled the heads only to find they were full of water. In my defense, it was the moron previous owner that removed the flappers. Needless to say, after calling around and finding out this was the problem, a new set was installed before the next outing

Op, you can get away without them, but just remember my story if you lock the engine up. Take a spark plug wrench with you to drain the heads.... Just in case

Originally Posted by thatsmrmastercraft

Without them there, you could get a surge of water up through the exhaust and possibly get as far as your engine. Worst case scenario would be to hydro-lock your engine. Get out a roll of duct tape and make them work. Then get some from your dealer or get them from skidim.

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[tommurtha]

I literally ran for YEARS, maybe even a decade, without them.... never a problem. Their main function IMO would be to stop a siphoning if an exhaust hose developed a leak and the boat was always in the water. With the height of the engine relative to the water line and the angle of the exhaust manifolds it would be highly unlikely to get water In. As for getting water into the block while loading .. not a chance The flaps don't seal. If one was at speed and did an abrupt slow down I can see maybe water entering to the muffler but as I said I ran for a very long time mainly in the course with stops at each end usually with never an issue