traumamed

TL;DR: Is it possible to end up in a situation where a transom assembly cannot be replaced once removed until the transom itself is rebuilt due to surprise rot?

I have a 1996 PowerQuest 340 Vyper with twin 496 HOs and Bravo drives. My port transom assembly has the common leak through the upper swivel shaft seal. From the looks of the transom assembly, it has already had the upper swivel shaft and seal replaced once by the previous owner. There are plastic inserts sealed into each side of the transom assembly where access holes were previously cut. On further inspection from inside the engine compartment, the studs around the backing plate look pretty rusted as does the Y-pipe, and overall I think the best way to tackle this job is just to replace the entire transom assembly rather than attempt a second repair of the swivel pin and seal. Not really a hard job on paper, probably wouldn't take me more than 1-2 days.

However - what I really do NOT want to get into is a transom rebuild, which brings me to my question. This is a 1996 boat. It has been cared for well over the years. It has always lived on a trailer, never in the water. I have no obvious indications the transom is wet or rotten. But it is a 1996 boat. It has probably been leaking at least a small amount of water through the swivel shaft seal for some time based on the look of things. Is there a chance that I could end up in a position where I take the old transom assembly off, only to discover it would be impossible to mount a new one due to pervasive, previously undiscovered rot? Worst case for me would be to end up in a Humpty Dumpty situation and have to face down an unexpected major resto project vs parting it out.

jeff32

jeff32

traumamed

Thanks jeff32. I do have access to a decent moisture meter. I didn't think to hit the transom with it because I didn't think they were reliable through gel coat and fiberglass. But hey, what can it hurt? I'll see what it shows.

scoflaw

Have a 99 PQ with the same issue. After removal of the TA I had some localized rot around the 4 lower TA studs. I hogged out all the rot and filled it back in with Jamestown dist. 5 to 1 epoxy, about a half a gallons worth. Problem solved. PQ didn't seal the inner edge of the keyhole, and that foam rubber Merc gasket is a total POS. 4200'ed both sides of the gasket on the install

jeff32

scoflaw

The fiberglass on the PQ transom is about a half inch thick on the outside, thinner on the inside

dlogvine

if you already removed the engine it is a matter of a couple hours to disassemble transom. It is an easy task - V-pipe 4bolts, transom plate 6 or 8 depending on what outdrive you have. If you suspect the transom to be this damaged, so you cannot install it back, than it is more dangerous to take this boat in the water, or if you decide to sell the boat it would be a huge liability on your hands. I would check it out. You can even try to drill a couple holes (make sure they are not going completely through transom, tape about 1/2 inch of the drill bit and stop at the tape) in the transom and look at the shavings. If they are light wood color, you are fine, if they are dark brown or dark red and wet, you probably want to rebuild your transom.

traumamed

Job now done, half a year later lol. A few months ago I found a local dealer offloading new old stock Bravo Magnum transom assemblies for a ridiculously low price, so I grabbed one. I then let it sit in the garage and stared at it for two months before biting the bullet and hoping for the best. I decided to have a mechanic I trust do the bulk of the work. I pulled the steering and drive myself and took it to him for the rest. When he got the port motor and transom assembly out, to my pleasant surprise (and his shock), the transom was completely dry. Not one bit of rot or moisture... on a 24 year old boat. Lucky me!

There were a couple of extra things needing attention as with any big job like this, such as Y pipe delete because it was rusted badly, new motor mounts, and a couple other little things, but overall it could have been way worse. So I just figured I'd update in case anyone else is looking at the same job. I read all these horror stories on rotted transoms, and of course they do happen, but my boat is proof that there are at least some older boats out there that are still dry. Now the transom assembly itself was another story. I had no idea they could rust out as badly as this one was. It wasn't even salvageable as a core. Internally it looked like a a half-dissolved Alka-Seltzer tab. I should've taken pictures.

smashm

Great news. Went through the same thing on my 95 Fountain. Had to replace one transom assy out of the three (other two were already done) last year. Worried for days that I would pull it apart & have a bigger mess on my hands. Pulled it, perfectly dry & preserved. Had a cpl large drinks to celebrate.