Cobaltchat.com

Anyone replaced a transom assembly? Mine fractured.

Do you mean part of the stern drive or part of the boat? My guess is it's part of the drive, but I haven't heard of many such problems.

Outdrive units seem to be anywhere from $1k-4k depending on new/used and other such factors, but the upper and lower units are also available separately from dealers such as: https://powerboatsupply.com/mercruiser/ ... 1973-1991/

The install might be the more expensive part of the fix. Please do keep us posted, and best of luck finding a quick repair.

"Do you mean part of the stern drive or part of the boat?"

The drive is fine. The assembly that attaches to the transom and that the drive attaches to, not so much.

Mercruiser or Volvo? Either one, transom assembly replacement is a engine out job. They don't typically "crack" they usually last the life of the boat, but salt water boats tend to have more problems / corrosion that dictate it eventually being replaced. Are you maybe talking about the bell housing? That is what the out drive actually bolts up to.

"Mercruiser or Volvo?"

Merc, A1G1.

"Are you maybe talking about the bell housing?"

Nope. The entire assembly.

I unknowingly cracked it three months ago, when I hit something. Had the drive replaced. Then three months of use caused those hairline cracks to fracture. That's why I'm now in the weird position of having a good drive, but shot transom assembly.

The good news is that I now know what was causing the slow infusion of water into the engine compartment.

I've never actually done that job myself - I did about everything else when I had my SeaRay with an Alpha I Gen II. I do know it's an engine out job - also I would plan on possibly some other jobs while the engine is out. You don't say how old the boat is or what model (assume it's a Cobalt), but if it's an Alpha Gen I it's old and the leaking through the transom assembly and possibly just from age you could have some issues to deal with around the transom cutout. Two other items to carefully inspect and consider replacing are the coupler and the Y pipe - both would be engine out jobs on their own. Once the engine is out none of these items are too difficult.

It sounds like it's probably this part that cracked. Hopefully their price is an anomaly, and you can find something cheaper!

https://www.dougrussell.com/mercruiser- ... 000cp.html

Thanks, John.

That is the assembly. Their price is for new. There are far less expensive used ones for sale.

b: Thanks for the tips.

I just posted the link because I learned something new trying to understand the problem you were having. And I now have one additional expensive thing to worry about going wrong on my boat :/ Thanks for keeping us posted,

John

All fixed.

One issue might help others: The assembly cracks started as hairline, then after 3 months of use, became complete fractures. If you're inspecting your assembly/drive, look carefully for those hairlines. If we had spotted them earlier, I could've avoided a catastrophic failure -- and being stranded and towed.

And one bizarre issue: After the fracturing/catastrophic failure, the arms of the assembly and the drive separated from the transom. They were held there only by the boots (which are new). If those boots had not held, she would have sunk.