When is it time to retire a Bravo 3 (260DA)

Hi. Pretty new to the forum and Sundancer ownership. How can you tell when it's time to retire a bravo 3 outdrive. I have a fair bit of corrosion on the cavitation plate and a bit around where the prop meets the lower end. Might have been on somewhat of a hot dock last summer I guess. Was shifting and working fine though. Might have clinked a bit when going into gear I guess. Not too bad. Just not sure if I'll be asking for trouble next season if I dont get it replaced. What's the going price something like that anyhow? It's on a 2000 260 sundancer with a 5.7. Is it better to go with a bravo 2 instead of the 3? Not sure what performance I'd loose. Corrosion resistance is said to be better with the 2s. Is this true?

A replacement BIII is not cheap, so as long as it is working fine I would live with the cosmetics and just run it - maybe do some sanding/painting to clean up the corrosion and make sure you have the right anodes on it. The final demise is going to be an issue with the cone clutch, seals leaking or leaking around the bearing carrier from corrosion. With a unit that old that is suffering corrosion damage none of those items are worth the $$ to repair, I would invest in a new drive at that point. In the meantime, I would clean it up as good as you can and live with it while it is running ok - also pay attention to the transom assembly and steering pin, another week point on the BIII setup.

As far as BIII vs BII - the BII is about bullet proof, doesn't suffer the corrosion issues the BIII does - But, it doesn't perform nearly as well, especially in a single engine application. The newer BIII (post 2003 or so) have additional anodes on the cavitation plate and the prop shaft, this dramatically helps with corrosion control.

How do I know so much about BIII's? My 290DA had twins BIIIs, the old style, I had corrosion problems and got both drives replaced under warranty - the new drives with extra anodes never had an issue. Mine were corroded so bad I was surprised they still ran ok, but they did - other than looking really bad the always performed perfectly. Mercruiser blamed it on a malfunctioning Mercathode system and recommend going to magnesium anodes.

Thanks for sharing your knowledge BillK2632! I really appreciate it. This sounds like a very reasonable course. Appreciated. I'm in salt water so I thing that magnesiums would dissolve in a week. Heck the aluminums go in about 2 months. She's on a trailer for the winter so that should keep things under control for now. I need to find that steering pin location.

I had a corrosion problem with the BIII on my 225WE and I eventually solved it through several measures (including upgrading the MerCathode system, adding the newer style sacrificial anode on the prop hub, switching to aluminum sacrificial anodes, and installing and maintaining all of the wires and connections on the continuity circuit). The drive wasn’t pretty, but in my case the only area that really risked ruining the drive through penetrating corrosion and water entry was around the bearing carrier, which is where that big chunk of exposed stainless steel from those two props is in closest proximity to the aluminum drive housing. I think that may be the same thing as what you are referring to as the area between the prop and the lower unit. If so, you may be able to save the drive, or at least extend its useful life, by replacing the bearing carrier.

If your aluminums are going in 2 months , your mercathode isn't working or your in a hot marina. You don't want a B2 for that boat.

scoflaw said:

If your aluminums are going in 2 months , your mercathode isn't working or your in a hot marina. You don't want a B2 for that boat.

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I agree. I’m wet slipped in salt water.

The aluminum anodes last the entire 6 months. The worst one is the horse shoe on the forward edge of the cavitation plate.

You should have your slip checked for stray current.

Thanks to all. I'll take the advice that a B2 won't work well on a 260DA. I do figure they put the B3 on there for a reason. I think I'll try cleaning it up and painting it for the coming season. I bought the boat in the water last Spring and was able to get it onto a trailer in the Fall. Now that I have the trailer the anode maintenance should be easier. Yep, aluminum anodes are all you can get around here. I wish there was a thread on checking a slip for "hotness". Seems like something that one could do with a multimeter. Also "upgrading the mercathode system". How's that done? The mercruiser shop couldn't even test the thing (or had no idea how to)..

I had mine replaced that was on my 496 Mag in my 280DA. It had been in the river about 12 years at that point. The thing that killed me was the electrical leakage into the water from our shore power at the dock. It just ate away on my drive. Back then it was $7500.00 to replace the BIII.

FishOn said:

Thanks to all. I'll take the advice that a B2 won't work well on a 260DA. I do figure they put the B3 on there for a reason. I think I'll try cleaning it up and painting it for the coming season. I bought the boat in the water last Spring and was able to get it onto a trailer in the Fall. Now that I have the trailer the anode maintenance should be easier. Yep, aluminum anodes are all you can get around here. I wish there was a thread on checking a slip for "hotness". Seems like something that one could do with a multimeter. Also "upgrading the mercathode system". How's that done? The mercruiser shop couldn't even test the thing (or had no idea how to)..

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During my BIII debalacle, the SeaRay dealer that I bought the boat from handled everything. Mercruiser sent someone out to my marina a couple of times to test, check the shorepower etc. He had a probe that connected to a multimeter that he was using to check for stray current in the water. I won't try and explain it, but it all goes back to the periodic table of elements, galvanic corrosion between dissimilar metals and hull potential (is your boat providing the ground path for the boats around you). I made sure I was there everytime - they (Mercruiser - in a professional way) tried to blame it on everything except a problem with the drive or Mercathode system. First it was the shorepower (no) then it was the sailboat next to me (no) then the wiring to the lift across from me (no) then the anodes had not be replaced (SeaRay dealer did all the servicing). They finally ran out of things to blame it on and ordered up two new drives - root cause was the Mercathode controller was faulty. They also had me switch to magnesium anodes (freshwater). Since it was a big warranty claim, things moved slow, my drives look bad, really bad, but surprisingly they continued to perform perfectly. I was very happy with the new drives, when I sold the boat 4yrs later they still looked new. My point is a Mercruiser dealer should be familiar with the testing, but in most cases with a BIII the issue is the drive design - on the old models there is just not enough anodes to overcome the the galvanic corrosion between the SS propellers and the aluminum drive housing. As soon as there is any compromise in the paint, the corrosion starts. With the newer ones with the extra anodes and coated bearing carrier, it seems to be manageable with diligent maintenance. Best course if you can (not always possible) is to keep an outdrive powered boat dry stored.

FishOn said:

Also "upgrading the mercathode system". How's that done? The mercruiser shop couldn't even test the thing (or had no idea how to)..

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There are black, blue, and red MerCathode controllers. Apparently the red one was introduced later and has higher output than the others.

D#%$ed Bravo 3's. Thanks for all the comments. It sounds the best thing is to keep them out of the water...

FishOn said:

D#%$ed Bravo 3's. Thanks for all the comments. It sounds the best thing is to keep them out of the water...

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Well yeah, but lots of people keep their outdrive boats in the water, it just takes some knowledge diligence on maintenance. The upside is it is hard to beat the performance of a twin prop sterndrive, .

Bravo 3s are wonderful outdrives but they require a lot of care and maintenance. The dual stainless props coupled with the aluminum housing are the root cause. In water (especially salty) if any of the AL is exposed it in essence turns it into a big battery with the housing being the anode.

The trick in salt water to keep them running well is multipart and very much related to chemistry:
1) Start each season with good paint - if staying in the water use a proper paint like Trilux 33 - I don't care if its ugly and not shiny as it will not matter if your drives melt away.
2) Bottom Paint - there needs to be a 1.5 inch space between the bottom paint and and metal portion of the drive transom housing.
3) Bonding - if all the bonding wires are not properly connected you leave your drive exposed.
4) Mercathode - it needs to be functions - think of it a defense shield for your drive
5) Anodes - Proper selection is important (AL for Saltwater) and get a good quality grade - not the cheapest 'zincs' in the store.
6) Proper Anode Prep - when replacing anodes take the time to clean the surface making sure a good solid is made to the housing or component below. Do not paint surfaces below anodes.
7) Add protection - if you have an older B3 without and prop anode then you should add one its a simple job and minor annual expensive to protect an expensive drive.
8) Inspection - regularly check all your zincs if possible - compare them if one side or even one anode seems to be wearing faster than another check it out. Case in point here I "lost" an anode on one of my south bay strainer - turned out it looks like the bonding wire was not properly attached as the connector cracked inside the plastic sleeve.
9) Environment - if all else fails look to the environment - you may have a "hot" dock or "hot" boat nearby. Ask your dockmates if they are having anode issues and work outward. Worst case get the meter and check it yourself.

Is this a lot of work? Probably not as bad as it sounds but well worth it to keep your drive running well. I had my B3 for 4 years (boat was 8/9 year when I got her) and had only minor work (a gimble bearing) outside annual maintenance and inspections.

-Kevin

Good advice. Thanks Kevin. I need to figure what I need to do to paint this unit before she goes back into the salt in the Spring. I've never done that before. Thinking Trilux 33 spray paint and primer.

FishOn said:

Good advice. Thanks Kevin. I need to figure what I need to do to paint this unit before she goes back into the salt in the Spring. I've never done that before. Thinking Trilux 33 spray paint and primer.

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When I had to clean to bear metal I always used Primocon spray to prep. For the Trilux 33 I painted from a can. I put on a thick cost (its not very pretty) as they recommend "Do not apply thin coats." The paint dries fairly quick and the idea is to build up big coating.

http://www.yachtpaint.com/LiteratureCentre/trilux-33-info-usa-eng.pdf

-Kevin

Did all of the above (actually my dealer did) and got 12 years out of my BIII. I actually think that is pretty good for a fresh water boat. Painted them with the “ugly” paint early on. Every couple of years got the 3M abrasive pads out and attached all the white rust forming on the housing and fins. I had a single 496 Mag and had 8 adults on the boat more than once and the old girl would still get up on plane with authority. BIII? Good to me....

So sanded down to shiny metal, got rid of flaked paint, and scuffed up the good paint with 80 grit. Then 3 coats of Primocon and 2 coats of Trilux 33. Before and after photos of encouragement.

Thanks for all of the help!

FishOn said:

So sanded down to shiny metal, got rid of flaked paint, and scuffed up the good paint with 80 grit. Then 3 coats of Primocon and 2 coats of Trilux 33. Before and after photos of encouragement.View attachment 69475 View attachment 69476

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Looks pretty good all cleaned up and painted. Two things I would do now:
1. Noticed you cleaned the bottom paint away from the transom assembly - should be at least a 1" gap there.
2. You can add the propshaft anode to the older BIIIs, I would do that.

Thanks BillK. The PO told me that they used a paint on there that was OK to go up to the drive. In an abundance of caution I worked on that gap. That took some elbow grease. I might pretty it up a bit more but I think I have about an inch now. I still need to put the anodes back on. The PO had the wrong style on the trim rams. I know now that they should connect to the end of the cylinders. I am looking into the prop nut. This vintage of drive requires the conversion nut. Mercruiser offers one that is about $200. There is an aftermarket one on boatzincs for around $50. Has anyone used that one? Looking for any 1st hand experience.