outdrive corrosion, maybe time for repairs?

Ethan's Tank

Member
Jun 1, 2014
425
aquia creek.potomac river United States
Boat Info
2009 Searay sundancer 350DA with twin 496 seacores
2000 wellcraft 2600 martinique [old]
Engines
Mercruiser 350 5.7 EFI
So, I'm moving to a new marina, where I can keep my boat in year round [bubblers in the winter], only difference between my current marina and the new one is that once the boat gets on the travel lift / blocks, I can't do any work on it due to insurance purposes.
My boat is still on blocks now before I launch it and voyage over to the new marina, I am trying to get as much work done on it so I won't have to haul out for some time...[hopefully]
-Added an extra coat of bottom paint
-wash/wax/buff hull
Now on to mechanic stuff. I plan to change out the gear lube for the bravo3, after looking at the condition of the aluminum on the drive, I'm seriously considering to sand/clean/prep/primer/paint the outdrives. I've been researching the hell out of it and it seems like everyone is pulling the drive off the boat, gutting it and do the repairs in a shop. I am wondering if its possible to do the work with the drives still on the boat, if I pulled the props and taped all the openings. This is what it looks like today.
20180714_160506.jpg
20180714_160500.jpg
20180714_160455.jpg
20180714_160441.jpg


I was thinking to sand down [no sand blaster] the corrosive parts, use some jb weld to rebuild some of the pits, aluminiprep 33 to clean-etch, alodine as priming agent, then roll on TotalBoat antifouling outdrive paint...

Thoughts or experience with this?
 

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That's how I did mine, with the Alumaprep and alodine, and antifouling paint.
And that there is the very reason I went with v drives on our new boat.
 
That's how I did mine, with the Alumaprep and alodine, and antifouling paint.
And that there is the very reason I went with v drives on our new boat.

I do wish I went with the inboards rather than this setup.

When you did yours, did you do it with the drive still mounted on the boat or did you take everything apart and do it on land? Also how long did the paint last for you before you saw corrosion again?
 
The photos may indicate a lot more than cosmetic corrosion. The shaft seal carrier is aluminum and once it corrodes around the edge where t he seal fits, the seal will leak between the carrier and the seal. Before you realize it, or while you are avoiding pulling the drives and completely servicing them annually, the lower unit can fill with seawater and rust the heck out of shafts, bearings gears....i.e. that expensive stuff that is in the outdrive.

Here is a photo of a seal carrier that is a goner:
corrosion2.jpg


This guy had to buy 2 new Merc outdrives @ $6K ea to get going again and his weren't B-iii's.

I'd get an outdrive mechanic to service the drives and see what the lower unit looks like before spending a lot of time and $$ on paint and cosmetics.
 
The photos may indicate a lot more than cosmetic corrosion. The shaft seal carrier is aluminum and once it corrodes around the edge where t he seal fits, the seal will leak between the carrier and the seal. Before you realize it, or while you are avoiding pulling the drives and completely servicing them annually, the lower unit can fill with seawater and rust the heck out of shafts, bearings gears....i.e. that expensive stuff that is in the outdrive.

I'd get an outdrive mechanic to service the drives and see what the lower unit looks like before spending a lot of time and $$ on paint and cosmetics.

ThankS for posting that. Since I'm pulling off the props, I'll inspect the seals and see if they need to be replaced or if they are damaged. Unfortunately, around me there isn't that many mechanics that will be willing to come out to my Marina to take a look. In fact there aren't that many reliable mechanics around my way
 
I took my drive off, and my corrosion came back the next year, but not as bad.
Those drives are heavy, I made a rolling lift for it.
 
I took my drive off, and my corrosion came back the next year, but not as bad.
Those drives are heavy, I made a rolling lift for it.

Having a second set of hands is a big help. I lost a thumbnail last April. Squished by the B3 while moving it around. It took 9 months to grow out and look normal again!
 
I took my drive off, and my corrosion came back the next year, but not as bad.
Those drives are heavy, I made a rolling lift for it.

I've been tempted to take off the outdrives off and see all how hard it will be to take apart, etc. Just been warned that if I miss out on doing something, boat could take on water and/or I would break something.
 
I could be wrong, but I don't think you necessarily have to take it apart.
I did remove the props, but nothing else.
Two people could remove them fairly easy.
 
Isn`t what your pointing to the prop shaft zinc on that Bravo I?
MERC806188.jpg
Isn`t what your pointing to the prop shaft zinc on that Bravo I?
MERC806188.jpg


Sorry guys.......That is an internet photo I copied to show what happens when corrosion "creeps" around the opening on the outdrive. It happens to be from a Fountain somewhere up on the East coast. Nodoby down here in the Gulf coat area leaves outdrives in salt or brackish water.

My point was to try to convince the OP that regualr drive service, while inconvenient, is necessary and the best insurance against an outdrive failure. B-III's have a series of double seals that keep the grease in and the water out. It is a lot cheaper to reseal a lower unit than to replace it.

Sorry for the confusion, carry on...........
 
What is the life on these seals? I read somewhere they last around 1000hrs, given mine only had about 250hrs on both, but granted the boat is an 09. I bought in 2014, so I don't know the full service history on it. Also, probably need to buy some sst to get all that apart as well.
 
Major job to replace the seals. I would wait till they fail before replacing. Change your gear lube on a regular basis, you can tell when you start getting water in there.

Your not suppose to wait until your drive looks like that to start getting concerned.
 
Major job to replace the seals. I would wait till they fail before replacing. Change your gear lube on a regular basis, you can tell when you start getting water in there.

Your not suppose to wait until your drive looks like that to start getting concerned.
I'll change the lube this weekend to see if there is any milky in the lube when it comes out, it was a thing to do on my list before launching anyways
 
Major job to replace the seals. I would wait till they fail before replacing. Change your gear lube on a regular basis, you can tell when you start getting water in there.

Your not suppose to wait until your drive looks like that to start getting concerned.

So I finally got a chance to get to the boat after this rainy week, I just drained the lube from the outdrive and there seems to be some water in there.
There isn't a whole lot, but I did notice a lighter stream color from the old oil. I don't think I noticed this in the past years I've had the boat. If it's not completely white and milky, would it be safe to assume this is normal? Or should I find a mechanic to change out the seals for preventive maintenance?
It's hard to see in the pic since I took it after most of it drained out
20180726_171754.jpg
 

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Your drive looks rough from your pics and you do have some water in there. Maybe you can have someone look at the seal areas to see if there is enough metal left to make a reseal worth it.
 
Your drive looks rough from your pics and you do have some water in there. Maybe you can have someone look at the seal areas to see if there is enough metal left to make a reseal worth it.

I'll try to find a travel mechanic around my way. Hopefully this won't be a big job, sinking too much money to something not working.

I'm soda blasting the corrosion this weekend to prep for some paint. Good thing the aluminum is soft, the sandpaper I tried is smoothing out some of the corrosion
 

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