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185 OMC transom seal leak

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billpopp

New member
I have a finger-sized hole in the transom seal. Can this be repaired or does the seal have to be replaced? The boat is 1979 model year
 
I didn't expect that prompt response and wasn't watching emails for that, thank you. Do you have any idea how many hours a technician might require to make this repair (I can use that as a gauge for my own efforts -- like 2x or 3x). I have rebuilt the heads and replaced the stern drive by myself. My Cole's manual makes it look fairly straightforward as the intermediate housing apparently remains in place and the boot is attached to it with one large clamp. However, the manual states in Step 1.." if the engine must be removed", but this doesn't make sense given the photos and the lack of mention of reinstallation of the intermediate housing. Could it be that the large clamp on the intermediate housing is sometimes not screwdriver accessible unless the engine position moves?
 
I've read where it is possible to stretch it over the outdrive. IDK, never tried that, always pulled the drive. So, a few hours if all goes well on the earlier electric ahift models (77 & earlier).
I can't remember the shift cable arrangement on the mechanical shift like yours so I can't estimate the time for removing & reinstalling the drive.

Basically, remove drive, remove 22 screws (hopefully self tapping & nut nuts on the inside. Then remove the ring & pry any sealant to break the bond of rubber to transon. Flex bellows aft & undo the worm clamp. Remove old bellows, clean off old sealant from transom & reverse the steps to assemble.

To make it look nice, mask carefully to not make a new sealant mess. Wipe off extra sealant that will ooze out.

You have the last generation of bellows, the 22 screw variety. So the cutout in the transom is big & should give you easy access to the clamp. A 5/16" 1/4 drive swivel socket & foot long extension is your friend.
 

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Thanks again for the prompt reply and tips. FYI, this transom seal is fastened with wood screws. Additionally, I recall a comment in this forum suggesting that it could be stretched over the outdrive with some soapy water. Looks to me like that's worth a try, as it is a bit of pain to remove and reinstall the outdrive.
 
I will tell you how this finally worked out. A local tech thought it might damage the transom seal to stretch it over the longest section that includes the cavitation plate. I am going to see what happens as I am removing the old seal. Of course, I have to remove the quadrant gear to do all this.
 
Quadrant gear is just 3 bolts, 9/16 socket. I use a box wrench to break them loose then a 9/16 swivel socket, again 1/4 drive.
2 full sets of swivel sockets, SAE & Metric are your best friend.

I think stretcing it will be a challenge. If it was just the upper housing, no problem but over the lower, IDK.
 
Droid, I haven't completed this as I am awaiting some new heads and don't want to mess with the shift cables at this time. It appears that stretching that new seal over the cavitation plate is way too risky -- need to stretch it 3 inches further than I can stretch it manually.

On another note, I had water in cylinders 5 and 7 (a lot in 7) after sitting for a week or so post fresh water flush from a salt water fishing trip. The water apparently spread via the intake manifold to the top of the heads on either side when I was out with it -- no water in the oil pan. There wasn't any evidence of leaking at the head gasket, and I don't think the head warped or cracked, as the engine didn't overheat. Many of the valves froze up sitting over the winter, apparently due to the fact the top of engine oil/water emulsion contained salt. I assume that either the port exhaust manifold developed an internal leak (no cracks) or the water came from between the gasket and mating surface with the riser, the latter of which has happened before. There was some rust under the gasket on the manifold/riser interface. Also, I may have made a mistake by using stainless steel bolts to hold down the riser. I can't find any machine shops to pressure test the exhaust manifold, and am reluctant to buy another one if I don't need to ($300). The manifolds and risers are 20 years old but not many hours, and the boat is only exposed to salt water for a few days every other year or so, and then flushed. What do you think?
 
Water also flows through the intake manifold, so it could be just a leak in the gasket between the heads and the intake manifold, requiring a new gasket and reinstall the intake manifold. Seems like a more direct way to get water in the head and cylinders.
 
I vote for via the exhaust.
Take manifolds off, sit then at the angle they would sit on engine & fill with water via fwd hose. Fill until it flows out the riser. Let them sit & see if water materializes at the ports.

Since they normally remain full when engine is shut off, you will simulate that condition. Manifolds could leak while running but it would just go out with the exhaust.
 
Neal, I replaced the intake manifold gasket prior to this latest event, as after running at speed for a while, it would not troll or idle, and then was very hard to start. After replacing the gasket, it worked fine until this post-fishing trip situation with water in two cylinders. I am having a machine shop check the manifold for a crack, but there was nothing visible. The gasket was partially broken at one end, however. But for water to be in the two back cylinders on the port side would not have anything to do with the intake manifold as there is no intake manifold water passage at that end, right?

Droid, I will try that leak test with the risers on -- makes a lot of sense considering the fact the water leaked in over some time. But I can't replicate the riser/manifold interface surface condition as the risers have been removed. I will grind the mating surfaces level and join (with a new gasket) the two to do the test. This will tell if there is a leak inside the manifold and if not then the problem was the manifold/riser interface, right? The manifold interior throat wall has become pretty thin. The risers look fine.
 
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