Bravo III - Time to panic? Corrosion beyond repair?

[kfehriba]

All,

Purchased a 2002 24' Sundancer last fall. The previous owner did not keep the anodes fresh and unfortunately while my surveyor mentioned that the drive need to be refinished, he did not warn me to the extent of issues with these drives when not cared for. My novice $$ training.

I pulled my out drive due to pitting and deterioration intending to clean it up, prime, paint, replace bellows, etc. It seemed to be in decent but not great shape according to my untrained eye. Today, I took the props off and this is what I saw:



So the question is... how bad is this? Is there any remediation that can be done. Do I slap some primer, paint, etc. on it and plan on replacing the out drive next winter? Will this survive multiple seasons? Or is that bad enough that those who know would recommend against using that?

The boat is in fresh water (Nashville, TN) and is kept in a wet slip.

Best place for new drive if needed? Is it worth the difference in replacing the top half with the bottom half?

I've seen a lot of information on replacing the drive, how difficult is it to replace the housing that attaches to the transom?

Thanks for any input.

Kent

 

[scoflaw]

Yup it's ugly but, seeing it's a pond boat and your not planning any trans Atlantic crossings, I would do what you can with prep work and paint and work it till it don't work no more. Same goes for the transom assembly, which is no joke to replace. I would make my decision on how much water is coming in and how much oil is going out. Unless of course this is really bothering you and you got plenty of dough to throw at it. Your call.

 

[fwebster]

There is a shaft seal that keeps the outdrive lube in and the water out. That seal is located inside the housing where the prop shaft exits. If corrosion has run around the housing and into the surface adjoining the seal, no amount of paint/filler is going to make for a long tern solution and will be nothing more than a cosmetic short term fix. If you haven't had the drive serviced, get a Mercruiser mechanic to check the housing for corrosion in that area then make a repair/replace decision.

 

[Madifonzo]

Mine was in similar shape...not quite as bad but still concerning. You should get the drive pressure tested. I had my whole drive sandblasted then refinished it. Interlux tech support can give you a good process.

 

[Stray Cat]

The bearing carrier on the Bravo 3 drive is replaceable....ifin you can get them out. There are special Merc. tools required for removal. The side of my shaft output seals were becoming more exposed due to corrosion. My Merc mechanic is replacing both of mine @ around $500 per drive. I would only suggest the bearing carrier replacement if the gear case is in good condition....yours look suspect due to the neglegence of the previous owner.

Also a word on annodes in fresh water. I have found magnesium annodes replaced annually (along with a functional Mercathode system) really helps keep corrosion at bay on the gear case and the trim cylinders. Check with a Merc Tech in your area for what they recommend for your water(s). My first B3 drive (1999) looked like the one in your pics because I didn't know any better and used zinc annodes.

 

[kfehriba]

Thanks Jeff. I've moved to using Magnesium due to fresh water. I also am adding the prop nut anode.

 

[kfehriba]

Thanks for the feedback everyone. It sounds like nothing short of having a Mercruiser mechanic look at it will give me a definitive answer. Once everything is back together I'll take it to the mechanic to evaluate including the pressure test.

Thanks.

 

[ZZ13]

Along the lines of what Frank wrote, I replaced my bearing carriers last year. Found one prop shaft had been "grooved" by the seal that keeps the gear oil from leaking out. Was still good and sealed as is, but once the carrier was replaced and a new seal installed, not so good of a seal anymore. The mechanic said when/if meaningful leaking were to occur that he would recommend replacing the whole lower unit rather than just the prop shaft since the drives were 10 years old.

 

[jason78]

Bearing carrier probably needs to be replaced. It would be nice to see more pictures with the thrust washer removed, it will just slide off. (copper colored ring). This will allow us to see the seal between the shaft and the bearing carrier. I changed out one of my bearing carriers last year. Went well. I did have to heat up the lower unit to get it loose which as I understand is normally the only way to get them out if they have been on for a while. Agreed though we need to see more pictures of the lower unit and drive in general. In my case the lower gear casing is in good shape so changing the carrier was the right choice for me.

 

[lawndoctor]

I've been through corrosion problems with my BIII, and mine is in fresh water and is the same age as yours.

1. I agree with the others about the bearing carrier, I replaced mine a few years ago. It may do the trick for you, at least for a while.

2. Make sure you have the heavy duty MerCathode, check that it is connected properly, and test the boat when it is in the water. You need a reference electrode (http://www.boatzincs.com/corrosion-reference-electrode.html) and a multi meter, subject has been discussed at length on here.

3. Make sure the drive housing has a good coating of paint on it, so there is no bare metal is exposed on the drive.

4. Don't take as gospel that magnesium is the metal of choice for the sacrificial anodes. It may be right for your situation, or it may not. One thing you can do is ask others in the same area as you what they use and what their experience has been. I had magnesium on mine for several seasons, at the advice of the local MerCruiser dealer, and the corrosion was bad on the drive while the sacrificial anodes themselves were barely eaten. I took some good advice I got here on CSR, and tried Navalloy aluminum sacrificial anodes from a company called Performance Metal Products. (http://www.performancemetals.com/anodes/navalloy.shtml)

5. The drive is supposed to have a series of wires on the exterior of the drive and also inside the boat connecting all of the various metal parts of the drive into one circuit. They were all missing on my drive and I did not know the wires were supposed to be there, until I talked to a repair guy who had a booth at the NY Boat Show. The complete set of wires comes in a kit, MerCruiser part # 99940A2, costs about $25. (http://www.mercstuff.com/groundingkit.htm) Putting them on can be a PIA, but I think well worth it.

In my situation, last season was the first season I did #4 and #5 above, , and it was the first season I did not have appreciable corrosion on the outside of the drive, so I think the combination of the above elements finally made the difference for me.

Good luck.

 

[src]

In addition, the Mercathode system works better in fresh water if you have additional transom pucks installed. The increased surface area of the pucks does more for you than the additional current that the Mercathode Red system can push out. I saw that in a spec document for the system that I can't find at the moment.

Magnesium is good if your water is VERY clear, with very low particulates. Once you get into murkier water, it can start to work against you and increase the rate of corrosion. Make sure you talk to local boaters and mechanics rather than just picking a metal because it sounds good.

 

[jason78]

I've been through corrosion problems with my BIII, and mine is in fresh water and is the same age as yours.

1. I agree with the others about the bearing carrier, I replaced mine a few years ago. It may do the trick for you, at least for a while.

2. Make sure you have the heavy duty MerCathode, check that it is connected properly, and test the boat when it is in the water. You need a reference electrode (http://www.boatzincs.com/corrosion-reference-electrode.html) and a multi meter, subject has been discussed at length on here.

3. Make sure the drive housing has a good coating of paint on it, so there is no bare metal is exposed on the drive.

4. Don't take as gospel that magnesium is the metal of choice for the sacrificial anodes. It may be right for your situation, or it may not. One thing you can do is ask others in the same area as you what they use and what their experience has been. I had magnesium on mine for several seasons, at the advice of the local MerCruiser dealer, and the corrosion was bad on the drive while the sacrificial anodes themselves were barely eaten. I took some good advice I got here on CSR, and tried Navalloy aluminum sacrificial anodes from a company called Performance Metal Products. (http://www.performancemetals.com/anodes/navalloy.shtml)

5. The drive is supposed to have a series of wires on the exterior of the drive and also inside the boat connecting all of the various metal parts of the drive into one circuit. They were all missing on my drive and I did not know the wires were supposed to be there, until I talked to a repair guy who had a booth at the NY Boat Show. The complete set of wires comes in a kit, MerCruiser part # 99940A2, costs about $25. (http://www.mercstuff.com/groundingkit.htm) Putting them on can be a PIA, but I think well worth it.

In my situation, last season was the first season I did #4 and #5 above, , and it was the first season I did not have appreciable corrosion on the outside of the drive, so I think the combination of the above elements finally made the difference for me.

Good luck.

This is great advice!