kidturbo

Well I can point you in the direction of the person to ask. Or wait until we Crack them open on landing, then we will all learn how they work... After filling them with oil again yesterdays, I can say one is open, other one is not. Filling that cavity with a syringe, you can feel more back pressure on that port drive. The one that is not open into the other cavities is the one with clear oil in picture above. So the vac theory goes out the window..

kidturbo

Been thinking maybe we need to bring one of these guys onboard for some technical support. They seem to have the surface drive issues figured out. And are into the big power diesels.

302Sport

I mean the diesel/Arneson setup is pretty proven and standard......LOL

SammyJ

Have you checked the prop shaft seals......
I had a similar issue with one of my drives years ago, water was getting in and we could not figure out how..
Like you the drive had been apart 3x times, new seals, gaskets, bellows etc, when I redid it the last time it was pressure tested in a tank and it was fine....
I put the drive on with fresh oil and launched but something came up and I couldn't get off the dock for 2 days.
Prior to getting out the as I was cleaning the shop I spotted a part (turns out it was a spare) that I thought I left out so I pulled the boat and pulled the drive..... when I started to drain the fresh oil, it was full of water......

• I'll leave out the expletives but it turned out that Merc supplied a bad batch of shaft seals for the drive. they kept the oil in, but not the water out... sitting at 48" down, there was enough water pressure to weep into the lower case.
• it was something to do with a double lip seal

I'm sure you've checked it all but this is just my $.02 from a similar experience

frickstyle

Ken,

I had a very slightly pinched/sliced O-ring between the upper and lower once in a SSM 5 drive. The big o-ring that went around the perimeter edge of the split in a groove.

It was very hard to detect, and a VERY slow leak. Did you do a pressure/leak-down test on the units? With bubbles at the splits? It was pretty hard to find the issues on mine. Very slight. Would suck in water when it cooled down after a run.

kidturbo

I spotted these today, and though what a shame they are stuck living behind little 800hp gas engines. I mean why carry a spare, your never gonna need it. LOL.

But I did notice they use a T-bolt clamp on the bellows rather than spiral hose clamps. Which makes me wonder if that might be a fix. Next trip out I'm gonna make sure the extension boxes are bone dry, and check for water hourly while she's floating. Right now, it's sure looking like a bellows related issue. We replaced that port one, and put new clamps on it last time the lower was off.

kidturbo

Like 4 times.. Replaced the seals a year ago cause they were leaking oil out.. Then rebuilt both lowers, with new seals in May 2020. And last in the pics a few posts back, you can see these have a separated cavity on prop shaft, and that was only place where oil was clear. So 99.99% sure it's not those seals leaking.. But your on the right track for std Merc setups. Couple days ago the prop shafts topic came up with couple experienced Merc techs. Guess it's been noted before due to prop vibration causing those seals to leak. But in our case, it's the one thing I can safely say isn't the issue.

kidturbo

Got that crack in upper box on Stbd welded yesterday. So today decided put a little primer on that patch and the skegs I drug through the sand and oyster bed two weeks back. Since purchasing these drives we've paid 3 different professionals to repaint them with high dollar Alwgrip or Emron. Until they prove worthy, they are getting $7.00 rattle can from here on out. I did spring for roll of tape and some plastic to keep the over spray off the Emron.

kidturbo

Last time apart, after finding a small tear along edge of the port bellows, and a trashed pair of U-Joints from salt water, we drilled a small hole in the upper case bearing carrier. That way any water in the bellows "Should" run into the extension box where you can see it. However after setting a turbo blanket on fire and having to wash dry chemical extinguisher off the engines, I got water back in the boxes and never dried it up. So when she was setting in water for 3 days, I couldn't determine if the water came in thru bellows or from the garden hose.

As I learned couple days back, I can't pressurize the bellows now from the lowers. The weep hole is behind the upper gear reduction box, so only way to plug the hole is stick a cork in it from inside, the reinstall the bellows and check with soap. Then ya gotta take bellows off again and remove cork.. But I did hit em with soap really good, and didn't notice any bubbles on the side you can see. As posted above, gonna dry up the extension box and maybe stick a camera in there on time laps mode for an overnight inspection.

Gimme Fuel

I have found that Rust Oleum Appliance Epoxy spray paint makes darn good drive paint. Just give good time to dry between coats, will orange peel easily if not. Decent shine and quite durable.