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scottyfum
05-23-2010, 08:52 PM
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
05-23-2010, 09:26 PM
I believe they help keep water out of the exhaust

east tx skier
05-23-2010, 09:30 PM
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
05-23-2010, 09:39 PM
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
05-23-2010, 09:53 PM
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
05-23-2010, 10:04 PM
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
05-24-2010, 10:14 AM
Do not remove them.

SJ02
06-03-2018, 10:01 PM
I have new ones if anyone needs them. Send me a p.m.

paco_06
06-05-2018, 11:21 AM
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;)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.

Sent from my XT1030 using Tapatalk

tommurtha
06-05-2018, 11:59 AM
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

paco_06
06-05-2018, 01:22 PM
I literally ran for years without them too. This is what I just mentioned. Every time you back out in the water you're taking a chance. Only takes one time to ruin your day which is what happened to me. Y'all do what you want to, for me, they'll always be on my boat because water can and absolutely will come back through the risers into the combustion chambers.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

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88 PS190
06-05-2018, 02:05 PM
They probably wouldn't do all that much against a siphon but possibly.

The only time I've been sitting around our boat and said to myself - man those flappers are doing something was when we were at a sandbar a few years back, gals were sitting up in the boat listening to tunes, including two lounging on the bow, the guys were in the water drinking beers and hanging out and the bow was way down, swim platform up out of the water from the weight forwards in the boat and a couple of big boats went by tossing wakes that just exploded right on the stern of the boat. I'm fairly confident that if the mufflers were full of water leaned forwards like that those wakes would have gone up to the engine. I'd bet if you own an open bow boat this could be a real issue when you dropped a skier if you had people up front with out the flappers as well.

tommurtha
06-05-2018, 03:21 PM
respectfully I can't see how backing into the water could ever get to the riser there is at least a 1 foot rise from the pipe to the riser. . Just floating allows water in as the flaps are not even close to sealed. I'm not saying they shouldn't be replaced only that any risk is negligible IMO. BTW I've been in a Mastercraft for nearly 40 years.

dvsone79
06-05-2018, 03:29 PM
Do people leave the flaps on when they install FAE?

tmothy07
06-05-2018, 03:31 PM
Do people leave the flaps on when they install FAE?

I don't think that'd be possible. The FAE attaches where the flaps would be.

kscrib
06-05-2018, 04:12 PM
Not to challenge everyone out here, but our X23 right from the factory does not have rubber flaps. There is a metal area in the center of the exhaust, but there is also an area all the way around the outer edge of the exhaust that is never covered.

masterx10
06-05-2018, 05:37 PM
Do people leave the flaps on when they install FAE?

My FAE came with flappers

babymoore3
06-08-2018, 08:12 AM
If someone ran an engine with vegetable oil instead of engine oil without problems, would you do it?

Because someone can or has doesn’t mean you should.

Probability or insurance..... $30 for flaps or $1500 for rebuilding engine after water enters....

JimN
06-08-2018, 08:53 AM
respectfully I can't see how backing into the water could ever get to the riser there is at least a 1 foot rise from the pipe to the riser. . Just floating allows water in as the flaps are not even close to sealed. I'm not saying they shouldn't be replaced only that any risk is negligible IMO. BTW I've been in a Mastercraft for nearly 40 years.

If the boat isn't running and a wave comes toward the boat, the flappers stop the water from being forced in. Also, a ski boat sits low in the water, so the difference between the water level and the riser is small- water doesn't have much problem getting into the exhaust system and if a wave comes from behind when the engine is off, the pressure can easily cause water to go farther since the water has already found its own level. I have seen engines that needed to be replaced because someone did a flat spin, too.

Miss Rita
06-08-2018, 10:04 AM
I ran for a very long time mainly in the course with stops at each end usually with never an issue

Yep. You can also argue that "I've not worn seatbelt for years, never had a problem".

The point is, when you need them, you REALLY need them.