1973 MR-1 Hull Seal

[1stgenbird]

I have a 1973 Silverline 19' in generally good condition. It has the 165 HP Mercruiser and what I believe is a MR1 outdrive. The last time I had it in the water was the summer of '16 when it developed a water leak around the outdrive. Circumstances last summer prevented me from even removing the shrinkwrap from winter storage so I did not use the boat at all.
This year I wanted to get the leak resolved so I took it to a local marina and after cursory inspection, I was told the transom is probably rotted and I should get rid of the boat.
As the boat was well cared for it's entire life, I find a rotted transom is hard to believe. I think the marina just didn't want to work on an old boat. In 2013, the same marina sealed the hull/outdrive withe silicone caulk and it had been dry for 4 years.
I will probably take care of the repair myself and the first thing I'm thinking of is to replace the gasket between the hull and outdrive and replace the two zincs that go through the hull. Does anyone know where I can get a gasket? I can't seem to find one for this year and model outdrive.

 

[Bondo]

I find a rotted transom is hard to believe. I think the marina just didn't want to work on an old boat. In 2013, the same marina sealed the hull/outdrive withe silicone caulk

Ayuh,.... I don't,....

Ya gotta pull the drive, then the motor, then the transom assembly to replace what ya wanta replace,....
By that time, the rot in the transom should be obvious,....

The aluminum bolts, 'n zincs should be easy to come by, as they're the same as the Alpha,....
The seal, I donno,..... might have to build yer own,...

 

[Alumarine]

The gimbal housing to transom gasket part number might be 27-65373 or 27-70974 depending on the version.
They are still available.

 

[1stgenbird]

Thanks, I will check out the #s. Ii know probably depending on the outdrive S/N.

 

[Bt Doctur]

You could try jumping on the drive to see if there is any flexing . If it moves, its rotted

 

[1stgenbird]

You could try jumping on the drive to see if there is any flexing . If it moves, its rotted

Didn't consider that. I'll give it a try.

 

[fishrdan]

Check the gaskets closely, the bottom part is different between the 2.

Besides the zincs, you'll probably need the anode bolts. They are made from a special alloy and most likely rotted/corroded through after 45 years, probably snap in half when removed. $30 or so for the bolt set.

Agree with the others on the rotten transom, check it closely. 45 years and a leaky transom gasket....I hauled my old 72 SeaSwirl to the dump due to a rotted transom and a soft deck spot, not worth it to rebuild (to me).