Water getting in.............

sogood

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May 11, 2016
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I recently took my boat ashore for some general repairs and maintenance. High on the list is finding where it's taking on water. Quite a lot of water as it happens. Details are it has an Alpha 1 Gen 1 outdrive, the leg on which has to be, (unfortunately) raised fully when moored, as my mooring drains dry on low tide.
The bilge was empty on low tide, but as soon as the tide rose, so also did the water in the bilge. My bilge pump, which had been working, seems to have failed just before the most recent ingress. So far, investigations have shown that the exhaust bellows was completely split apart, but this apparently, shouldn't allow water into the bilge.
As far as I can see, the U joint bellows is fully intact and tightly clamped, as is the shift bellows. Further investigation will follow when my hinge pin tool arrives, allowing me to dismantle things further.
I was going to allow some water to run into the exhaust outlet, from outside the boat, to see if it rant back inside into the bilge, suggesting an issue with the Y pipe. Thoughts on this or any other approach?
The entire leg assembly is securely bolted up to the transom, nice and tight, and I'm confident that it wouldn't allow such a volume of water into the boat. This all happened without the engine running and happened in tandem with the rising tide.
I've already checked any thru-hulls while the boat was afloat and these all check out fine.
Anywhere else I should be looking? Thanks in advance.
 

achris

More fish than mountain goat
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May 19, 2004
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One possibility the springs to mind is that an exhaust shutter has broken off, lodged in the bottom of the pipe and worn a hole through the pipe...
 

sogood

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One possibility the springs to mind is that an exhaust shutter has broken off, lodged in the bottom of the pipe and worn a hole through the pipe...

Thanks for that. I had replaced the exhaust shutters, but at the time, only one was present in the exhaust. There was no sign at all of the other one, even after scoping down the exhaust pipe. I haven't found any remnants either after looking in from the opposite end, now that I have the drive off, but I'll take another look see. This is why I thought that by running some water back into the exhaust outlet it might show up in the bilge. Thanks again.
 

wahlejim

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Jul 23, 2015
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Either bellows or gaskets around trim line manifold, y-pipe, or transom gasket. Does the amount of water increase when you are underway?
 

sogood

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Bellows checks out fine. What's a trim line manifold? The boat was on its mooring, sitting at low tide on a mud bottom. When the tide rose, so did the water in the boat. Thanks for the input.
 

Mad Props

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What's your method of checking when you say your drive is bolted to the transom nice and tight?
 

sogood

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Dancing on it, with no movement or flex. No water seeping back out of bilge around the leg/ transom mating surface.
 

Grub54891

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Is it possible that when the tide comes in, the boat is sitting at an angle, and water can come in through the bilge pump thru hull? As the boat rises, it levels out and the thru hull comes out of the water.
 

sogood

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The bilge thru hull is far enough above the waterline not to have anything flowing back in, even at an angle. And the boat levels out quickly enough as the tide rises. There seemed to be a flow/ movement of water at the transom when I last saw it coming in. Weather won't allow me to do much today but I will update as I progress. Thanks for the input .
 

achris

More fish than mountain goat
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.... What's a trim line manifold? ....

Where the trim ram hoses come together at the bottom of the gimbal housing. The 4 hoses go into that manifold. It has a gasket under it. The 'topside' of that manifold has 2 hose, UP and DOWN... They go back to the pump. I have never seen that gasket leak, but that doesn't mean it can't... Worth just looking at that though. DO NOT try to remove it if it looks ok...

Chris.....
(Called 'connector' in the drawing below...)

trim2.JPG

trim1.JPG
 

poconojoe

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I'd like to follow this to see how you make out. I thought maybe bellows...but I know you said the other two bellows looked good.
Timing is everything. I'm wondering when the water starts to enter in relation to the rising tide. Does it start immediately (may be bilge plug related), when the water is at trim hose height (as Chris was asking), at bellows height or when the leg of the drive becomes submerged (as you were suspecting)?
 

wahlejim

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achris there was a recent topic on here where someone took on water from that manifold. He had taken it off to address some trim issues and re-installed with the old gaskets, one of which had a tear and allowed a decent amount of water in. With the boat sinking into mud with the tide, I was thinking may the trim lines were getting caught up and pulling on the manifold, eventually loosening it over time.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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. So far, investigations have shown that the exhaust bellows was completely split apart, but this apparently, shouldn't allow water into the bilge.
As far as I can see, the U joint bellows is fully intact and tightly clamped, as is the shift bellows. Further investigation will follow when my hinge pin tool arrives, allowing me to dismantle things further.

if your exhaust bellows are gone, the shift bellows and u-joint bellows may not be far behind. rubber life is based on calendar

I would replace all the bellows, check the gimble and alignment while the drive is off.

I would then back the boat into the water while on the trailer, and with a flashlight, mirrors, and a camera phone, look for the water coming in.
 

Rick Stephens

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I have seen, and created, a not quite flat transom surface that had a low spot that didn't quite seal. I was able to seal mine up by adding a little bit of torque to the transom bolts and nuts. I did this CAREFULLY. All my bolts were new and I didn't reef on them. Old studs and bolts are something to be careful of when tightening.

My point isn't that you should just go to retorquing the transom plate, but to consider possibility that it can appear tight enough to have no wriggle but still have a gap in the gasket letting water in. It is really tough to see water coming in that way. Have to look very closely at the keyhole with the engine in the way.
 

scoflaw

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Jun 2, 2010
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I have seen, and created, a not quite flat transom surface that had a low spot that didn't quite seal. I was able to seal mine up by adding a little bit of torque to the transom bolts and nuts. I did this CAREFULLY. All my bolts were new and I didn't reef on them. Old studs and bolts are something to be careful of when tightening.

My point isn't that you should just go to retorquing the transom plate, but to consider possibility that it can appear tight enough to have no wriggle but still have a gap in the gasket letting water in. It is really tough to see water coming in that way. Have to look very closely at the keyhole with the engine in the way.

This^^^ happens often and that OEM Mercruiser 10 dollar foam rubber transom assembly gasket is a joke. A gasket this important should be made out of better material, like real rubber. Like said, if your transom wasn't dead flat to begin with, this could be your source. Let it go for a few years leads to rotten wood, most key holes aren't sealed.
 

sogood

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Just a bit of an update and a question. Having probed as far as I can while waiting for my "Mercruiser special Tool" to remove the bellhousing, I found that the U joint bellows seems to have come adrift from the flange/pipe in at the transom end. I don't think the fact that I have to leave the leg fully raised when moored, as the mooring dries out fully at low tide, has helped matters. I'll be able to check things out more fully once the bellhousing is removed. My question is this. While poking about I came across a sort of rubber ring, or 3/4 of one. This is about the same diameter as the U joint bellows and is castellated on one side, like the pattern on the leg where it meets the rest of the outdrive. I cant find this part on any parts diagrams and my usual supplier isn't familiar with it either.
Any thoughts on what this is and what's it's purpose. Thanks in advance and updates will follow.
 

poconojoe

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Can you post a picture of this "rubber ring"? Could it be part of a torn bellows?
And now at least you know where the water was coming in! I only hope your u-joints are not rusted. And your gimbal bearing most likely needs replacing too. A complete bellows and gimbal replacement and you're good to go.
 

Scott06

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Apr 20, 2014
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Most likely this is the big rubber ring seal that comes with the outdrive gasket

it it goes inside the bell housing and seals the round part of the outdrive where the input shaft is. I believe it seals any water that may get by the shift shaft seals in the bellhousing from getting into the bellows
 
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