water entering thru bottom of transom SX Cobra

workkyle

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May 12, 2020
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I have a 1998 Volvo Penta 5.0 GL with a OMC SX Cobra sterndrive. I have owned the boat one year and last season no water leaks. This winter I removed the sterndrive and inspected the gimble bearing, bellows and u joints. All looked good. No signs of water or lube. I did replace the exhaust bellows it was busted in half along with the water pipe oring and the 2 orings on the driveshaft. Started the boat on water ears. No leaks. Put in the lake and water was coming in like a faucet was on slightly. Can't see exactly were from but at bottom of transom a couple inches above the drain plug. Did my ujoint just happen to go or do I have another issue. any helpful ideas would be appreciated. Kyle
 

Lou C

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OK the bellows on the Volvo SX is the same as the one on the OMC Cobra, and on the gimble housing side there is one thing to be aware of, there is a groove in the gimble housing flange that fits into a ridge in the inner surface of the bellows here are some pix (hope they show up) to illustrate. I heard that Volvo changed the bellows from this design to something more durable but I haven't seen one...anyway I replaced mine back in '16 and no leaks, I did use OMC gasket sealer on the gimble housing flange and some OMC triple guard grease on the pivot housing end...as per the OMC shop manual....
 

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Scott Danforth

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you have a 22 year old boat...... how is the transom?
 

workkyle

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Sorry for slow reply i was in the woods playing all week. So just to clarify, the boat sat in the water all last year and never took on any water. I replaced the exhaust bellows. The u joint bellows looked good. Put the boat in the water and it was leaking when motor is not running. I realize the boat is old but hard to believe removing the foot made the transom leak.
 

workkyle

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Thanks Lou The pics help understand the ujoint bellows better. You said OMC gasket sealer I think that is different than bellows adhesive. The gasket sealer is a temporary holding method for the soft parts correct?
 

vasy

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Thanks Lou The pics help understand the ujoint bellows better. You said OMC gasket sealer I think that is different than bellows adhesive. The gasket sealer is a temporary holding method for the soft parts correct?

I'm not sure how this would matter. Exhaust bellow is not needed for operation and even if it was not there, would not cause water to get into the boat.

I'd buy a camera on amazon, attach to your tablet and look where is the water is coming from.
https://www.amazon.com/dp/B07YD1TZRV

Funny enough mine is also starting a tiny leak, will be doing some tracing. Could be transom seals are going or transom itself, possible transportation of the boat put extra strain on the old component and help developed a leak.
Maybe you accidently pocked a hole in a u-join bellow while doing work or put an extra strain on it causing to separate?
 

workkyle

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Can the water pickup tube oring (square with semi circle) allow water into boat? I'm wondering if this moved on me since I used grease for install instead of adhesive. I pulled sterndrive back off and inspected the u joints bellows it was dry and showed no cracks or tears in bellows. The water pickup oring looked ok but was slightly pulled out of slot after seperating sterndrive. Placed it back with grease and still leaking into boat at same spot. Will try and get video of leak today. Thanks for input hopefully it's not a rotted transom
 

Greg O.

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My 89 cobra was leaking water. It turned out the bolts that hold the exhaust Y pipe to the transom bracket had worked loose. I didn't see it until I removed the engine. I'm not sure I could have gotten to them anyway on my boat without removing the engine.
 
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Greg O.

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This is the exhaust Y pipe (#55) I was talking about. The four bolts (#57)at the bottom were loose.
 

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workkyle

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Thanks Greg O. The water entering is just below the Y pipe but it's impossible to see exactly. I'm sure my bolts will be near impossible to get to. I take it these bolts are plugging holes. Did u put sealant on them or just tighten
 
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workkyle

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Thanks Greg O, the water entering my boat is just below the Y pipe but it's impossible to see exactly. I'm sure my bolts will be near impossible to get to. I take it these bolts are plugging holes. Did u put sealant on them or just tighten
 

workkyle

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Finally got a pic of leak. Any input on source would be appreciated. Lou C Greg O. Scott Danforth Also I want to thank everyone for input to date. My thoughts on leak source are u joint bellows (inspected twice so far), shift cable hose or transom to transom plate? Lou
Kyle
 

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Scott Danforth

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see post #9

time to pull the drive, pull the motor then pull the transom shield and inspect everything as you pull things apart
 

Westieman

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IMG_20200412_155802497 (2).jpg My boat has had some water infiltration issues, but the previous owner " forgot " to mention those. After pulling the engine I found one issue. As you can see on the pictures, the Y-pipe is in very bad shape, as is the transom plate. The gasket worked its way out on two places. Maybe you will need to check this on your boat. IMG_20200412_155722565 (1).jpg
 

workkyle

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awesome pics, thanks!!!!!!! engine removal will begin after auto bilge allows boat to sink or this winter. I put her on the shore everyday for now
 
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