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Leaking transom after service.

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mattryan

New member
Hi all.

Just had my mercruiser service a month ago. Finally got it in the water and its leaking heavily behind the transom plate. Taken it back to the mechanic and so far he thinks nothing is wrong from his end?

It never leaked before? Is there anything obvious that he could of done that could cause this leak? Its the first time Ive used him and he seems like a good genuine guy? It wasnt leaking before the service though? I have a video, will try to post it.

He is still trying to find the source of the leak, said it could be a corroded hole in transom shield or bullhorn?? Going to tip boat up and fill with water to see where it comes out?
 
Here is a link to the video. Its a drop box link, if you click it it will try to get you to sign up to drop box. You dont need a drop box account, the video will play with out it.

Note when you click the link a box will come up to put your details in, just close that and then click the video and it will play. You dont need to sign up to dropbox.


https://www.dropbox.com/s/pjy9mqvxm9wrb10/Video (2).MOV?dl=0
 
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The water is actually flowing over the transom plate its just that the light is bad, its not coming from between the bottom of the plate and the transom.
 
I Guess I dont want to believe its corrosion as the boat and motor ater in great condition and only used in fresh water. Tahoe 2008. IMG_0160.jpgIMG_0159.jpg
 
On the outside transom, at the bottom where the trim lines go in.
there is a Zink there.
Did the mechanic replace it?

If he did he may have forgotten the gasket or he messed something up there.

You have a gross leak.

If he refuses to find it, do this.

With the plug in the transom, boat on the trailer drive trimmed up as in the picture.

Raise the front of the trailer as high as you can without making contact with the drive/transom to the pavement.

Put garden hose inside boat into bilge area and fill with water until you see water coming out the outside around or at bottom of transom assembly.

DO NOT OVER FILL INSIDE to where the water is making contact with the starter. You should find the leak before that.

Have had to do this to find tough leaks many times!! quick and effective!
 
kghost said:
On the outside transom, at the bottom where the trim lines go in.
there is a Zink there.
Did the mechanic replace it?

If he did he may have forgotten the gasket or he messed something up there.

You have a gross leak.

If he refuses to find it, do this.

With the plug in the transom, boat on the trailer drive trimmed up as in the picture.

Raise the front of the trailer as high as you can without making contact with the drive/transom to the pavement.

Put garden hose inside boat into bilge area and fill with water until you see water coming out the outside around or at bottom of transom assembly.

DO NOT OVER FILL INSIDE to where the water is making contact with the starter. You should find the leak before that.

Have had to do this to find tough leaks many times!! quick and effective!
Click to expand...

Thanks, the mechanic is actually going through this today, filling boat with water tipped up. . I dont believe he replaced any anodes? They all look perfect? As I dont know what is involved in removing the leg I wondered if it was even possible for the mechanic to cause this leak? Cheers.
 
That is a gross leak so find out exactly what the service guy did ,remove, inspect, etc. Last time I saw something like that the rubber grommet was not installed under the zinc or mercathode
See if you can put a business card between the transom and the bottom of the housing. Maybe the drive took a hard hit on the bottom and sheared the anode bolts.
 
mattryan said:
Drive never hit anything. He can’t find the source, mercruiser tech coming out to check it out.
Click to expand...

Boat mech still has no idea where the leak is, he has checked and double checked everything he did in the service when removing the leg, thinks it could possibly be a corroded hole in the transom shield or bullhorn, Couldnt find it by putting water in the boat, taking it now to the closest boat ramp as a last ditch effort before removing the motor to gain access to the rear of the transom. :(


Is this now pointing to anything more likely now that you guys may think of???
 
Docksidemarineservices said:
By the stains on the transom this may have been leaking slowly for a while and finally gave way....That is a large leak, I would inspect the exhaust Y pipe.
Click to expand...



Apparently its leaking between the transom shield and the transom? But he is not sure where? How do these seal? Does the gymbil housing external create the water tight seal or is the the plate on the inside of the transom?
 
The transom assembly, on the outside has a large grove and a even larger O-Ring that gets compressed to the outer transom.

There are several thru bolts that tighten the two halfs together. all are tightened inside except the bottom two.
The bottom two are tightened from the outside and typically have zink ball caps that are threaded over the bolt end.
 
Jack, the anode bolts are tightened from the inside, the zinc anodes just thread on to the end

2Q==
 
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kghost said:
The transom assembly, on the outside has a large grove and a even larger O-Ring that gets compressed to the outer transom.

There are several thru bolts that tighten the two halfs together. all are tightened inside except the bottom two.
The bottom two are tightened from the outside and typically have zink ball caps that are threaded over the bolt end.
Click to expand...


So then Im guessing the motor has to come out to get access to undo those bolts and check all that check all of that. Bummer!! This is getting very expensive!!!
 
see if you can push a business card between the housing and the hull first.If No, then its doubtful the transom is the leak.
First remove the drive and verify no water in the main bellow.
Using a hose nozzle spray water at the housing to see if water enters the boat.Spray inside the exaust opening too.

Second step , remove the motor and reinstall drive. visit a ramp and see where it comes in from
 
Yes the engine has to come out..... Transom assembly leaks don't just happen. Tension was lost on the transom assembly either the bolts/washers rotted, or the transom rotted.
 
Docksidemarineservices said:
Yes the engine has to come out..... Transom assembly leaks don't just happen. Tension was lost on the transom assembly either the bolts/washers rotted, or the transom rotted.
Click to expand...

Bottom two bolts were corroded down to about 6 to 8mm. Transom looks ok but thinking I might drill a few holes in from the back.

The main problem I can see, if I place a straight edge across the bottom where the transom sits you can see the transom appears to of been compressed by the weight of the leg approx 0.5mm, or when it was glassed it wasn't perfect, or worst case water has seeped in to the timber causing it to compressed? Hence why Im thinking of drilling some holes from the rear.

However digging around with a small screw driver in those bottom holes the timber feels solid?

I also put a volt meter in all the holes and get a reading through the bottom 2 holes yet none of the others. So there is some moisture in there.

The question is when or what is enough of an indicator to replace the transom, or can I just let it dry out, put a skim coat on the outside to make up the .5mm difference and go from there. will try to post some pics later.
 
Pull the boat apart. Check the integrity of the wood, 1/2 a MM is not going to make a difference.

Drill some holes and let it dry out if wet...The old guys at the marina I work out of, use acetone to chase the moisture out.
 
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