Transom Leak

madbd5

Cadet
Joined
Apr 12, 2010
Messages
7
Hello All, I have a 94 Chaparral 1830SS with a 4.3L Mercruiser and Alpha 1 outdrive. Last season I replaced a torn shift cable bellows. Towards the end of the season I noticed water entering the bilge area, again! (about 1" per 3-4mins) Kicking myself for not replacing the other bellows I took the boat to the lake, backed in the trailer, and watched as water leaked in through the drive shaft opening behind the engine (very difficult to see btw). I pulled the outdrive and to my surprise I find the inside of the u-joint bellows bone dry... along with the outdrive shaft and no rust anywhere. I suppose the only thing left could be the main seal between the inner and out transom assemblies?? What do you all think and is there a way to further narrow this down? I checked the rotation of the gimble bearing, it's smooth but I can definitely feel something (slight) while rotating. I appreciate your feedback in advance!
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Transom Leak

How interesting. I also have a 4.3 with a new water leak problem. My engine's been in and out a few times over the last few years :rolleyes: and I also have no idea where it's currently letting water in.

What I will be doing, and I suggest you may wish to try the same thing, is to remove the drive, pull the engine (which you would have to do anyway to replace the transom seal), re-install the drive (fit a cover or long hose to the water tube) and take it back the the water and back the boat in and see where the water's coming in....

I'll keep you informed through this thread, as I intend to pull my engine tomorrow morning as I still have to replace the timing cover, again. :facepalm:

Chris.......
 

Bondo

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Staff member
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Apr 17, 2002
Messages
70,465
Re: Transom Leak

I suppose the only thing left could be the main seal between the inner and out transom assemblies??

Ayuh,... If by chance that Is the problem,...
It's usually caused by a Rotten transom...
 

1987sylvanoffshore

Seaman Apprentice
Joined
Apr 7, 2010
Messages
46
Re: Transom Leak

Are you sure that is where the water is coming from? Could it be the anode gasket going bad? (The anode that your hydraulic lines go to)
I'm just throwing some things out there.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Transom Leak

Found my leak... Broken hose clamp on the hose that feeds into the fuel pump cooler.. Easy fix, but still had to pull the engine to get the new clamp on. I will update my 'cracked timing cover' thread when I find out if this time I've fixed it....
 

madbd5

Cadet
Joined
Apr 12, 2010
Messages
7
Re: Transom Leak

Did you by chance take any pictures during your repairs? Unfortunately, I have to acquire an engine hoist before I can pull my engine. Last year during my rebuild it consisted of a tree and 1/2 ton air hoist....
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Transom Leak

Engine's still out. What pictures would you like?
 

cannonford57

Petty Officer 1st Class
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Mar 5, 2008
Messages
353
Re: Transom Leak

achris,i know you meant the power steering cooler but just to be sure.......just asking
 

achris

More fish than mountain goat
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May 19, 2004
Messages
27,468
Re: Transom Leak

achris,i know you meant the power steering cooler but just to be sure.......just asking

No, I meant the fuel pump cooler. I have an MPI engine and it has a cooled fuel pump.... Strangely enough it has the word 'Cool-fuel' on the side of the housing.... (see attached photo) Inside that housing is a copper water tube and a high pressure fuel pump. They are coupled with a copper plate and heatsink compound...
 

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madbd5

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Apr 12, 2010
Messages
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Re: Transom Leak

Thinking of other ways to check for a tear in the bellows I placed a flashlight inside of it and turned off all the lights in the garage, move around the swivel ring hoping to see light, nothing. So I figure I'll check the transom bolts and if any are loose it could point to a transom issue :( lastly if I must, pull the motor and diagnose further. I good clear shot of the inner transom plate would be helpful.
 

cannonford57

Petty Officer 1st Class
Joined
Mar 5, 2008
Messages
353
Re: Transom Leak

madbd,one way if possible is to jack the bow of the boat up as high as you can,put in the plug,pop the hose in and have a beverage while it fills.of course watching the starter and other important things making sure they dont get wet.i've had loose exhaust horns and bottom anode bolts show up this way.good luck
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Transom Leak

i stand corrected achris.no disrespect intended

None taken... See the hose clamp on the right of the fuel cooler? That's the replacement for the one that broke....
 

madbd5

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Apr 12, 2010
Messages
7
Re: Transom Leak

And the verdict is.....see picture. I'm relieved and not at the same time :cool: Exhaust shutters are getting replaced, Mercruiser 807166A3 correct part (replaces 14348)? And then to deal with the hole. How much pressure typically builds at WOT in these pipes?
 

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achris

More fish than mountain goat
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May 19, 2004
Messages
27,468
Re: Transom Leak

Now THAT is very interesting... That is EXACTLY what happened to my 1994 unit (before the current engine). When you pull the engine you'll find that your exhaust shutteres are gone. The hole in the bottom of the exhaust pipe has been caused by one of the broken shutters lodging in the bend, vibrating and wearing a hole. You can have the pipe welded up by a decent ali welder, and fit the new style exhaust shutters.

Chris......
Another thing I found on my old 4.3LX was a loss of top end revs once the engine had warmed up. That's caused by a resistive connection between the engine block and the distributor body. You'll find there is a 'spare' grond wire in the harness right next to the distributor. Remove one of the ignition module screws on the distributor and put that wire there.

Good luck....
 

twostroke87

Petty Officer 2nd Class
Joined
Nov 15, 2008
Messages
137
Re: Transom Leak

I thought I replied to this but i guess not..

Either you try to plug that hole, or you pull your engine and replace your Y pipe.

I would atleast try to plug it and see if it works. If it does, keep an eye on it. If it doesn't...your pulling your engine.
 
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