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topic 20415

Mercruiser Bravo III Stern-Drive, Layman's Idea for Corrosion Abatement


Dear readers,

First, off, I know next to nothing about the technologies of metal finishing in general and corrosion prevention and abatement in particular. I am the owner of a boat (Bayliner 2858) that has a Mercruiser Bravo III stern drive. This stern drive unit has particularly severe galvanic action corrosion problems which have been aggravated due to poor design that does not allow for placement of adequate zinc anodes. The unit is located totally below the water line and includes 2 large stainless steel props in close proximity to the aluminum gear housing. The boat is not trailerable and remains in the water continuously during the boating season. Most of the time the boat sits in a slip, not being used. During the times of non-use, it occurred to me that the galvanic action might be abated by creating a non-conductive barrier between the props (which are in-line and a little bit larger than the proverbial bread box) and the gear housing. I was thinking that this might be accomplished by simply enclosing the stainless steel props in a large plastic trash-bag or perhaps some stronger type of rubberized bag, but I would sure like this "amateurish" solution to be gut-checked by some professionals in the field before applying it... due to the fear of adverse consequences that I am too ignorant to recognize.

Anyhow, I would very much appreciate someone out there would indulge a non-schooled person such as myself with a quick reading as to whether this is a whacky idea or something that might be helpful (or at least not harmful).

Thanx in advance!

Steve P [last name deleted for privacy by Editor]
retired - Springfield, Virginia


I have seen a discussion of this problem in Boat USA magazine. Boat USA claims that corrosion is worse on this double-prop model than single prop drives, implying that it has to do with the exceptionally large cathodic area of the double stainless steel props and lack of room for anodes where they need to be.

Mercruiser Stern Drives

You may want to look at III.asp [Ed. note: that link no longer functional]

Mercruiser claims that there is no problem. One of their largest dealers claims it is a "wonderful drive" and it is "up to the CUSTOMER to educate himself about galvanic corrosion and how to protect his boat." (see

While you are sort of on the right track, I don't think your plan will really work unless you could get those props completely sealed. I would think that C-clamping a zinc anode to the props during storage would be more effective than the plastic bag, but I am afraid that either "fix" is dangerous because of the possibility of forgetting they are there and starting up the engine. I would not want to be responsible for a chunk of zinc whirling around on a prop until flung off at high speed.

The only answer seems to be to buy a second cathodic protection system from Mercruiser per the previously mentioned dealer web page, and then if it corrodes anyway, blame the boat next to you, the marina owner, the steel-reinforced sea wall down the road. Then blame yourself because the manufacturer accepts no responsibility.

The dealer page I referenced also warns that the Mercathode systems will drain the battery, so you must also install shore power on risk of your boat sinking when no power remains for the bilge pump.

Ted Mooney, Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey


I agree completely. I have a 2000 Rinker with a 7.4L MPI and Bravo III. Performance is great, but the corrosion is undeniably the fault of the manufacturer.

I received today my formal notification that Mercruiser will not do anything to assist in repairing my corroded Bravo III. First sent to the dealer in October, 2002, they procrastinated and ultimately told me I needed to do a hull potential test. I paid for that to be done, which involved putting the boat back in the water. It checked out exactly as their corrosion prevention manual specifies. So, the dealer faxed the information back to Mercruiser.

Their response was that it is now out of the corrosion warranty period and no defect in parts or workmanship were determined found. Therefore, I could have saved myself the time and effort by simply paying for the drive to be repaired up front.

You're right, as an engineer, I can see right through the 'Customer Service' department they have. They are simply trained 'front men', who are instructed to deliver the predetermined 'Assistance Rejected' response. They will not give you the number to the people who actually make the decisions because they know there is no good response why the drives are corroding to pieces.

I keep looking for a class-action lawsuit to get started. One was started in Florida, but only 8-9 people contacted the attorney so he dropped it. This will be the only way the issue will be adequately addressed. If anyone knows of another lawsuit, please reply.


Arlian B [last name deleted for privacy by Editor]
- Philadelphia, Pennsylvania


This issue, as mentioned, has been a big one with Boat U.S. I also read several other boating forums and it was all over all of them.

Speaking for myself, I can't afford a big enough boat for a Volvo Penta to be practical, so when we got rid of our older Mercruiser powered boat last year, we went with an outboard this time.

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey


I appreciate the need for protecting my Bravo-III drive with a Mercathode system and keeping the zincs in good shape. But what if I never leave my boat in the water; aren't these systems only effective on a boat that is sitting at the dock? If so, would I be wasting my money to purchase a Mercathode system as long as I'm only trailering my boat to/from the Chesapeake Bay? Would the zincs be sufficient, or do I need a Mercathode for those occasional times when I might pull in overnight at a marina?

Ellis S [last name deleted for privacy by Editor]
Coast Guard Auxiliary - Yorktown, Virginia


You have a problem on your hands, Captain, in that you are supposed to be counseled by the engineers at the manufacturer, who have test results and readings available--not by strangers on the Internet. But from the reports at BoatUS and the entries on many boating forums, and the letters sent here, it unfortunately appears that if you follow the manufacturer's advice you may still have trouble.

Someday one of those engineers may leave the company and become an expert witness, and we may find out the full facts one way or the other. In the meanwhile, as an amateur, I don't see how a dry motor can galvanically corrode because a galvanic circuit requires a difference in potential between two metals, a metallic path for the electrons to follow, and an ionic path for the metallic cations to follow. For the same reason that zinc anodes cannot protect an automobile from corrosion, I don't think an electronic system protects a boat at dry dock. But there may be more to it than my limited understanding.

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey


According to an e-mail from merc all bravo 3 drives already have Mercathode systems installed. Would I have to install a second system? Would a galvanic isolator help with these problems?

Craig L [last name deleted for privacy by Editor]
- West Islip, New York


I have some of the same Questions for the Bravo lll on prevention of corrosion. I am presently looking for the lowest replacement cost of a remanufactured unit, but my boat is in the water April to Nov. is this one going to have to be replaced in two to three years. Is there an answer to the problem, or should the props be replaced with alum. ones.

Joseph A [last name deleted for privacy by Editor]
- N.Valley Stream, New York


Mercruiser does not sell aluminum props for the Bravo Three unit. I was told that the outdrive is too powerful for props constructed of aluminum and will destroy them.

Curious, Volvo Penta has a 5.0 motor with a dual prop outdrive with aluminum props. I personally owned this unit for 11 years with no problems. It is still in operation by another owner with no problems.

I have been begging Mercruiser to help solve the corrosion problems with Bravo Three. Clearly they do not have an answer , thus the canned responses from their Customer Service dept.


Gary M [last name deleted for privacy by Editor]
- Middletown, Delaware


I too have a Bayliner 2858 year 2000. Engine hours are over 1000 and I have had nothing but problems with bravo 3. I have added Mercathode, used their recommended zincs, and stripped down and repainted the drive at least 5 times.

The area around the props is ate up bad and the lower unit is always losing paint and metal. I have done all the checks and seem to change zincs about every 2 months. Also I have changed the engine coupler 2 times, once while swinging on a mooring in the Bahamas.

So far I have spent thousands on trying to keep this drive working! Now it's broke down, something in the drive, gears, u-joint--god knows what! If I can change to a Volvo drive I would but I don't think I can. So my other option is to upgrade to a newer style Bravo 3 and hope that works. New units seem to cost around 5 to 7 thousand, thanks Mercruiser!

p.s. My Mercury 5 hp. on the dink has towed the boat over 50 miles, it's slow but has never failed me.

Keith L [last name deleted for privacy by Editor]
- Louisville, Kentucky


Well good luck or bad, it seems I'm putting on a new model Bravo 3. I hit something in the water at top speed. It broke the upper and lower cases, broke the upper and lower gears and damaged the engine coupler. The estimate for replacement plus labor is close to 11 thousand and insurance will cover it. I know what you're thinking, and no I didn't do this on purpose.

Keith L [returning]
- Louisville, Kentucky


I too have just pulled my Sundancer 260 out for the winter and my drive is severely eaten up by the issues that are mentioned here. Has anyone talked with a lawyer for class action status? Do other drives have the same issue? I am a little irritated since this is my first purchase!

Michael C [last name deleted for privacy by Editor]
- Moorestown New Jersey


I too am having severe problems with my 2002 bravo three being eaten away. The repair shop spent several hours today checking the boat, water, Mercathode, etc. All checked out fine. So why is my outdrive falling apart? Sounds Like Mercruiser needs to step up to the plate and fix this problem.

William N [last name deleted for privacy by Editor]
- Orange Park, Florida


I too own a Bravo III our first boat, equipped with 2 merc cathodes and changed the preferred zincs every 6 weeks this season. Pulled the boat out on Oct. 18TH and found bad corrosion on the lower unit. If the lower unit holds a pressure and vacuum test can I just replace the housing and use the internal parts? Did anyone have any help from Mercruiser. It is sad to see such a profitable company look the other way instead of backing up their product. Looking for some answers.

Joe O [last name deleted for privacy by Editor]
Maint. Supervisor - Bellmawr, New Jersey


I too had major corrosion problems when I took my 2002 Searay with Bravo Three drive out of the water this year the hoses for tilt & trim blew right out of drive had to unhook and til drive manually after bringing boat to dealer they contacted mercury and they replaced the drive under warranty....

I don't want this to happen again any suggestions?

Pat M [last name deleted for privacy by Editor]
- Setauket, New York


In 2002 I contacted mercruiser about the corrosion problem my new boat had and they did replace the housing only. I had to pay for the labor. now in 2004 I am back in the same boat with a lower unit that leaks oil and needing replacement from corrosion. mercruiser claims that the boat came with a 3 year corrosion warranty but only a one year with a replacement lower unit. why? It is a new lower unit. or is it a way for mercruiser to dodge the subject.What sucks is that I have a 2002 model and I heard they fixed the problem in 2003. Why can't they send a fix to me instead of a put off. If anyone wants to team up let me know. I am steamed and have a lot of time this winter to get even.

Todd S [last name deleted for privacy by Editor]
communications - Bettendorf, Iowa

Jan 21, 2005

I too have a 2000 rinker with a B-3 which I have just been told must be replaced. I am seriously considering suing mercruiser under the NJ consumer fraud laws (awareness of the problem without alerting buyers is sufficient cause of action, and it looks like there's more). I need an expert witness. Mr. Mooney?

Patrick C [last name deleted for privacy by Editor]
- Somers Point New Jersey

Jan 23, 2005

Sorry, Patrick, I haven't even seen one, so I'm no expert on them! I suggest you contact BoatUSA who is probably on top of this issue. I think you should start your search for an expert by talking to "marine surveyors" whose day-to-day job is inspecting boats and assessing their condition. Good luck.

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

Jan 31, 2005

Having read all of the submissions regarding B3's, I'm very concerned. I just purchased a 2005 Searay 260 with a single engine and B3. It hasn't been launched yet, but I plan to keep it in brackish water. Since this is a 2005 do you feel that many of the previous issues may have been resolved? And if not, how long can I expect before I begin seeing severe problems and wishing I had not purchased this boat?


Rory M [last name deleted for privacy by Editor]
Sales - Reston, Virginia

Feb 8, 2005

To my knowledge, Mercruiser never admitted that there was a problem so they can never claim that the problem is now fixed, Rory. But this is an industrial metal finishing site, and I don't keep on top of all the different topics people have introduced. Sorry.

I would suggest continuing to follow this at BoatUSA through the links listed above to see if Mercruiser has announced changes, or if BoatUSA has found improvement in later models. Good luck

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

Mar 12, 2005

Hi -

I found your string on the Bravo III Corrosion problems and posted a response, but for some reason it hasn't appeared in the string/link.

I'm the owner of a 2000 Crowline 268CR, and recently moved from Indiana to Florida. The boat was kept on an inland freshwater lake only in Indiana (Lake Patoka). I've owned the boat two years and it only has 120 hours.

After reading about the Bravo III problems on Boat.US, I had a second mercathode installed, a galvanic isolator, and changed the anodes to magnesium anodes as recommended by Mercruiser.

I didn't see my boat come out of the water last October, but when it was delivered to Florida last week I was disappointed to see the same corrosion problems everyone else seems to have on the lower unit. Some of the metal is gone, and there is quite a bit of white substance around the prop area. Obviously, I'm very concerned. I've followed all the recommendations for preventing this problem, but nothing really worked.

Now, my boat is in "Hi & Dry" Storage which means it will be lifted into/out of the water and flushed each time it is used on the Gulf of Mexico. I hope this will prevent further problems.

I haven't read any other current strings on this problem. Apparently, nobody has been successful in launching a class action suit. I'm not sure why. There certainly seem to be plenty of affected owners to interest an attorney.

Many years ago, I owned a very small motor home with a 4-cylinder diesel engine. The engines were blowing up. I never had a problem, but met a guy driving one at a Florida beach that told me about the problem and a class action suit they had started. I had to send in $500 to join the lawsuit. Several months later, it was settled and each of us received $5,000. Of course, we had to agree "not to discuss the problem with anyone". "Hush" money, I guess. I do hope someone gets a class action suit going, I'll gladly join. It's disturbing to invest $60,000+ into a boat and watch a critical component waste away.

Have you heard anything else?

John C [last name deleted for privacy by Editor]
- Homosassa, Florida

March 15, 2005

Hi, I have the same problem 2001 Cierra 2655 with B3... Now on second set of casings. All test done and results as per Merc maintenance manual. Second controller, aluminum anodes etc etc.. Corrosion continues - I'm on the west coast in salt water. Has anyone found a fix that works? if so please post details. I'm mad at merc too, but first want to stop the corrosion. Any leads anyone?


Burk Q [last name deleted for privacy by Editor]
- Vancouver, B.C., Canada

March 16, 2005

Hi Burk - Please explain what you mean when you say, "second set of casings"? The fixes I've seen suggested a second mercathode, galvanic isolator, and magnesium anodes for fresh water/zinc for salt water. Did I read your post correctly that you're using aluminum anodes? Sorry...I don't understand all this "mumbo jumbo". Like you, all I know is my stern drive is deteriorating due to corrosion. Incidentally, I also don't know the extent of my problem, just that some of the skeg is gone and there is a white substance behind the prop and blistering on the lower unit. I had planned on sanding, priming, and painting the affected areas with a TBT (tin based) Anti-fouling paint to try to stop the problem. I found a paint, prop & drive paint [linked by editor to product info at Amazon] (for aluminum drives); and primer, Primocon [linked by editor to product info at Amazon], but don't think they're TBT based (it appears TBT based paints aren't environment friendly and are being banned/replaced), but TBT was suggested by websites I've read.

Boat.US had posted a lawyer's address indicating a Class Action suit had been started. I called him, he indicated he settled a private lawsuit on his personal boat and was prevented from beginning a class action suit. However, he was interested in starting a class action using another lawyer and would help.

I'm currently trying to round-up the names, addresses, phone numbers, email addresses, etc. of affected owners. It'll take a lot of work. The lead plaintiff needs to be someone with a well-documented problem with the Bravo III. If you're interested, please send me your information. I'm hoping the other posters here also read this. My email is [my name as listed below, with a period between first and last name,]. I just hate to see large corporations not standing behind their products at the expense of the consumer.

John C [last name deleted for privacy by Editor]
- Homosassa, Florida

Ed. note: organo-tin coating are indeed environmentally hostile as they are very persistent. For this reason they are never allowed to be used except on aluminum (because copper based paints would destroy the aluminum rather than protect it) and in some areas I guess they're not even allowed then.

March 18, 2005

Hi John,

While I'm not so worried about legal action (as I guard my time off so much) I am definitely interested in a fix. I am working with a local merc dealer so far to no avail. I have alum anodes, two controllers and a galvanic isolator. I have changed both the upper and lower casings on the outdrive. While mine wasn't completely corroded through this is the trap. If you sand (not wire brush due corrosion) and fill and paint - the corrosion if it continued will be hidden behind the filler. First thing that will happen is the leg will leak oil and you will be replacing the whole leg. (Maybe) So I decided to change the casings out early.. Used ones are about 2500 in Canada.I still have not stopped the corrosion. I think the next attempt will be a big "Zinc" on the hull wired into the boats bonding system. Then perhaps an adjustable corrosion guard system. I can't believe someone out there doesn't have a fix. Keep me posted. There is quite a bit of info on "Bayliner owners forum" and etc etc.

Best Regards,

Burk Q [last name deleted for privacy by Editor]
- Vancouver, BC, Canada

April 13, 2005

It is interesting to read all of the same problems with the Bravo III. I too had the same problems with my 2001 B-3 and in 2003 was able to persuade Mercruiser to replace the outdrive. One season back in the water started to have the same results, so I sold the boat...didn't want the headaches. Problem is that many boat buyers know about the Bravo III as well, so I sold it for a lot less than what it was worth. I feel for you B-3 owners, and want to let you know this problem has been going on for a long time. I would think with a little effort, you could match lists from Boat US, this site, Bayliner and others and get enough owners to get your suit together. I don't own a B-3 now, but I sure would like to see Mercury pay for all of us that have had to suffer with the problems.

Greg S [last name deleted for privacy by Editor]
- Raleigh, North Carolina

April 13, 2005

I purchased a 2001 Searay Sundancer 24 in the fall of 2003,moored it from May to October of 2004 only to find the lower unit severely corroded and I am currently pricing a replacement lower unit. It was recommended by a Mercury mechanic that I follow these steps:
1 - sand and prime with a zinc chromate primer
2 - paint with Mercury phantom black
3 - use an anti-fouling aluminum paint for a final coat
4 - use aluminum anodes
5 - check that the mercathode is functioning properly

Ken B [last name deleted for privacy by Editor]
- Northport, New York

May 10, 2005

I own a 2000 Crownline LPX with a B3 prop and I just noticed last year that half of my skeg is missing. I thought I must have hit something but I didn't remember. It also didn't looked sort of chewed off.

The dealer that services my boat told me I need a new mercathode ($500)and weld a new skeg on ($600) and that's where I spotted all your stories about the famous Bravo 3 drive.

Now I realize that I didn't hit anything, it just fell off! Neither mechanic mentioned anything to that effect. Pieces of the drive systems falling off after only 5 years! This is a joke right?

Anyhow, I will be contacting Mercury to resolve this and count me in on a class action lawsuit!

Michael R [last name deleted for privacy by Editor]
- Toronto, Ontario, Canada

May 17, 2005

A MerCrusier rep suggested to me to connect another Mercathode in parallel to the one already fitted to the Bravo three using the existing anode,this increases the protection around the leg by twice as much, which helps the problem with having to run stainless props. That with a galvanic isolator in the earth wire of the shore power lead should solve these problems, you will need to have your battery charger on as the Mercathode's do draw a little power.

Neil C [last name deleted for privacy by Editor]
Boat owner - Mt Maunganui New Zealand

May 17, 2005

With regard to Bravo 3 Galvanic corrosion would putting the entire boat in a bag and putting a chlorine tablet in with it stop the galvanic action if the boat is in sea water that is or would the salt water have to be replaced with fresh water.

Neil C [returning]
Boat Owner - Mt Maunganui New Zealand

Ed. note: I don't really understand what you are describing, but chlorine is terribly corrosive to stainless steel, so I really don't get the concept.

May 27, 2005

Looks like everyone has a story on the Bravo III, and it looks like we all have the same ending. I have a Bayliner 2001 Ciera 2655 in San Diego and have been meticulous maintaining my boat from the day I bought it. I've changed the Zinc's regularly and have gone as far as buying a bottom liner to try to arrest the galvanic corrosion on the outdrive. This to say the least has been my personal battle from day one. After the batteries are charged I would unhook the dock electric every time I leave the marina to make sure that the Mercathode would not drain the batteries at the advise of my knowledgeable broker. I know it's had to believe, but there is one out here. I knew what I was getting into when I bought the boat with the Bravo III but thought if I just keep up with the Zincs I could prove everyone wrong. NOT!

To try answer your question Neil, I bought the liner to cut down the galvanic corrosion process as well as to keep the bottom clean after I had the outdrive repainted less then a year ago. I thought that was the answer. However, after a few months, I notice that the outdrive appeared to start showing signs, what looked like chemical corrosion (greenish/white color), like you would have from pool equipment from the chlorine. I thought I be smart by putting freshwater in the liner, what a genius I thought I was, freshwater in the liner and protection from all the other boats around me, run fresh water through the engine, man I thought I had it going on. NOT!

The galvanic corrosion again started, first started on the edges on the outdrive, with a whitish powder and turning my shiny prop black. I'm guessing the prop turn that color because of the chlorine, but I'm not a chemical Engineer or Scientist. Then the greenish color showed up on my rams and now looks worse then it did before I had it repainted.

There's a Bayliner 2001 Ciera 2455 with an Alpha I or II on it two slips down. It has a liner as well, and has the chlorine floater loaded with tablets most of the time. His outdrive still looks like it brand new. I know this guy well, and he doesn't take care of his boat a quarter of what I do.

Right now I'm thinking about having hauled out again and have the outdrive repainted and sell it before it's too late and I have to buy an outdrive, only to have the same thing happen. As you all know, Bayliner or Mercury will not cover the corrosion under warranty. However, I think there are enough of us out there with the same problem that we can draw more attention to this issue if we pounding on their door. So is it a Bayliner or Mercury issue? I think it's a Merc issue they designed it! I like Bayliners because they are affordable boats. Knowing what I know now about the Bravo III, I would stay as far away as I can from a boat that has one.

Your comments are welcome.

Dave M [last name deleted for privacy by Editor]
- San Diego, California

June 8, 2005

I'm convinced that there is and will never be any solution to the B-3 corrosion problem. I've owned a '97 Bayliner 2855 since new, and the lower casing was replaced in 2000....under warranty. It took over a year of my service manager fighting with Merc. The rep had claimed that I used the wrong zincs, when in fact I used their own product. They relented, and the casing was replaced, but the problem is of course still there. I am getting rid of the boat and getting a smaller boat with an Alpha I. Personally I'd like to see some more options. I'd really like to see a class-action lawsuit.

There's simply no way to stop the galvanic process when you've got a large quantity of very noble metal 1/8" from minimally noble metal. Merc is crazy to state that an aluminum prop can't handle the drive. It's 300 hp divided by two props. Are they stating that aluminum props can't handle 150 hp? Please......

Craig V [last name deleted for privacy by Editor]
- West Chester, Pennsylvania

June 9, 2005

If aluminum props can do it, Craig, why isn't some small manufacturer making their fortune by offering an aluminum prop for the Bravo III?

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

June 15, 2005

My 2005 Bayliner 275 with Mercruiser/Cumminsdiesel bIII is now in fresh water for about 2 months. Reading all your corrosion problems with the b3 I checked my drive every week.I saw last week a little corrosion on the edges from the skeg of my brand new drive. Anodes are magnesium and mercathode is working ok. To solve the problem, I ordered a second mercathode and spare props. I'm gonna paint the props 2 times with a 2-component epoxiprimer and finish it with epoxy black paint. I hope the epoxy will isolate the stainless steel from the drive. Has anyone tried this before?

Thanks, regards from Holland

Rudi H [last name deleted for privacy by Editor]
- Holland

June 21, 2005

I have tried epoxy paint on the drive and on the propellers. Theory is reducing the surface area of SS exposed may reduce the galvanic action. My boat is on the upper Chesapeake Bay, so the water is fresh to brackish. I must not be using the correct anodes, since they don't deteriorate and the Bravo III drive continues to disappear. The epoxy paint helps but doesn't eliminate the problem. I end up filling pits each year with epoxy putty and repainting just to get through. I replaced the drive in 2002. The factory installed "zinc" anodes did show deterioration, but the drive still corroded through the skeg in one season. I moor my boat. It has one Mercathode, but I'm unsure it ever worked. I'm more concerned with the boat sinking if the Mercathode system drains the battery and the bilge pump doesn't work. This year I have a new problem. The gimbal ring corroded where the steering shaft connects. As a result, the boat won't steer. Replacement is difficult and expensive, so it looks like another $1,600 dumped into this worthless piece of junk. My advice to anyone considering a Mercruiser Bravo III is "Run away, run as fast as you can". Mercruiser refuses to stand behind its' product. Their response to my complaints was that they never [heard] of this problem. Good luck, epoxy paint helps, but there is no solution to the Bravo III's problem other than maybe hitting a submerged object at full speed.

Gary F [last name deleted for privacy by Editor]
- Wilmington, Delaware

June 27, 2005

Hello all. Having just become aware of this issue, I'm quite honestly teetering between fear and anger. I currently have a 2002 SeaRay 240 Sundancer which has never been left in the water. The anodes (original) show a bit of wear but nothing impressive. My skeg is showing metal...quite a bit actually...but it looks chipped, not from bubbling. The Metal looks fine.

So from what I've read, I've got a ticking time bomb on my hands. So I'm going to summarize my questions/comments:

- I remember seeing testing procedures for the Mercathode somewhere in the shop manual. I'm going to find that for the very next time I'm in the water. Any "make sure you" type suggestions around this?
- Being that my drive is obviously attached, what is the best method to prep and paint the drive? And what paints/primers/coating/etc are best?
- I'll admit that I don't flush/wash my boat every time I pull her out. I'm going to be sure that is given due priority going forward. I'll probably add one of those handy flush units as well so that I can flush it when I'm a transient as well.

Thanks for any and all suggestions!

Jon M [last name deleted for privacy by Editor]
- Newark, Deleware

June 17, 2005

I stumbled across this forum while looking for other mercruiser info and started reading with interest as my brother has just fitted a bravo 3 to his boat and he will be operating in salt water.
I am in the marine electrical installation trade and some of the fixes will not work,in my experience corrosion always starts with exposed metal, i.e., paint chips and when you have a leg traveling at 30-40 knots thru water it will happen and that paint damage will turn the leg case in to an anode for the props and shafts and bearings, etc.
Prevention is difficult unless you inspect your case for micro paint damage after every use then as needed wash and repaint,could make boating day a long one.
As mentioned before about coating the props,the problem there is the prop/shaft electrical connection,
I wonder if mercathode is the answer or possible electrical separation from the boat electrical systems would slow the whole thing down,role on plastic legs.
I'm not sure I have the heart to tell my brother of your problems yet as his hard earned money is now spent and not in the water yet.
I think when his leg starts to rot sand blasting and epoxy may be my advice anything to stop the exposure the battery acid (i mean salt water) and large hull anodes.
good luck everyone.

Andrew P [last name deleted for privacy by Editor]
- Cornwall,UK

July 3, 2005

Hi, Jon.
What I know of epoxy paint on your drive/props is that you can use gelcoat barrier (gelshield), for aluminium (maybe in your country another name for the same product). Colors in grey and green.You have to paint it at least 3 to 4 times. After that you can finish it with epoxy black paint which must be easy to get in a good paint store.

Rudy H [last name deleted for privacy by Editor]
hobbyist - Holland

July 3, 2005

Last week I ordered the ss-props of my bravo 3-drive (spare ones) when I opened the package box, I checked the (very) expensive props and I saw big cracks on the inside of both props. I brought them back to the dealer. they said to me that they have never seen such damaged (new) props before. They changed the props for other ones. SAME PROBLEM! All big cracks inside. I saw 5 props with cracks. I'm gonna check the ss-props of my bravo-3X 2005 drive, maybe they are in the same poor condition. dealer will ask merc to give me guarantee that the cracked props will hold on extremely conditions. If one will break perhaps my whole drive will be damaged, and boat can sink. Not very safe boating with my family. Still don't have spare props. want my money back.
Am I alone here? Please clean your props, take the grease out, and check your bravo 3 props,
Regards from Holland.

Rudi H [returning] Hobbyist - Rijnsburg, Holland

July 7, 2005

I have been considering a Bravo 3 for a repower. Noting all the corrosion problems has led me to a small research of Corrosion Potentials of Metals. It would seem as though the Tin based paint that is recommended for the drives also makes the drive the anode to the Tin and the Stainless. Very few metals are Anodic to Aluminum, these are Lithium, Magnesium alloys, Zinc(plate), Beryllium, Cadmium, and Uranium(depleted). It would appear that the easiest access to any would be Magnesium. Many small engines (Volkswagen) used Magnesium blocks. Time to apply some networking and pool our resources to create an Anode that can protect these drives. Possibly a filled blanket draped over props with responsibility to remove it prior to starts would be a heck of a solution.

Alan A [last name deleted for privacy by Editor]
- Oak Harbor, Washington

July 9, 2005

I have been reading with great interest all the problems with the Bravo 111 and it just makes me wonder where it all went wrong. I have a Bertram 25 with twin 200 hp chevy engines as power plants hooked up to early model mercruiser 11 TRS legs and are having very little corrosion problems at all. The boat is moored in salt water and I am using just the standard zinc anodes on the boat with no mercathode system fitted.
I also run alloy props without any problems despite the horse power rating.
As far as keeping all the surfaces in good condition I use just a better than average epoxy finish on all the running gear then seal it with Internationals Intertuf23 which is a vinyl tar anticorrosive, I apply this using an airless spray system to get a good coverage in those difficult to get to areas.
I then top coat the whole transom and legs with 2 coats of Altex AF 3000 then coat the rest of the boat with 2 coats of International Intersmooth 360.
The legs get a full strip and re paint every 3 years but the antifouling is re done every 18 months and the boat is slipped and water blasted 2 to 3 times a year.
I have also been known to add a measured amount of a concentrated weed killer to the antifouling before applying it to the hull and transom area and believe me this works.
The only other thing I have considered is bagging the hull and legs when I am on the mooring and having the chlorine floater in the bag area.
It seams to me that the designers at Mercruiser have gone backwards instead of improving their product, it appears that their product has got substantially worse in the later models instead of better.
One other thing I have also noticed is that the more sophisticated the electronics on a boat, the more it seems prone to the old galvanic corrosion, My solution to that, is to throw away your computerized engine management system and go back to the good old fashioned carburetor and distributor and maybe run a totally separate electronic system for your accessories which is say solar charged and in no way connected to the engines or drive. Just a thought.

Peter C [last name deleted for privacy by Editor]
- Lake Macquarie, NSW, Australia

July 23, 2005


JOHN D [last name deleted for privacy by Editor]
- MAHOPAC, New York

July 31, 2005

Trying to cope as the rest of you are. Bought my Regal 2460 in 2001 with Bravo 3. As an ex-Navy man, I read all the manual from Mercury thoroughly, and had the Mercathode installed, despite the bewilderment of the dealer. Also insisted that 1 1/2 inches around the transom mount be free from paint. Dealer protested this, as he had already painted. But I insisted.

Always shut off shore power when I left boat - pulled out the plug. Better warm beer than a consumed drive. Even with a galvanic isolator, I didn't trust it.

Later I moved my boat to a mooring, and always raised the drive to trailer position, as high as possible, leaving the splash plate anode in the water. Theory: keep the SS props away from the tidal current, which can accelerate corrosion exponentially.

With less than 300 hours, my corrosion problems are small, some pitting on the bearing carrier anode, and some nicks on the edge of the skeg.

HOWEVER, that still does not solve the problem going forward.

Some alternatives, removing the Bravo 3 and replacing with a Bravo 2 or earlier, all of which feature both aluminum props and a bearing carrier anode - imagine! A bearing carrier anode on earlier AL prop models, and none on the Bravo 3.

I'm considering, at the present moment, installing AL rudder/trim tab anodes on the skeg. Either the 3 1/2 or 5 1/2 diameter. Keep in mind that doing this installs TWO anodes.

Am I afraid of "overprotecting"? Hardly. Merc, in their Corrosion "Guide" recommends adding a large transom block AL anode, plus a second Mercathode. In addition, in the 2004 model then offer a second splash plate anode, plus a prop nut anode. And they continue to recommend the Mercathode.

A dealer I talked to recalled that Merc representatives stressed the need to keep good electrical continuity. There are roughly six places on your drive which you must keep free of paint or other inhibitors to electric current. You can't trust any boat yard personnel to put on anti-fouling paint. You must do it yourself, making sure you apply masking tape to anodes and electrical contacts. While the boat yard owner knows how to do it, it will be delegated to the closest illegal alien who can hold a paint brush.

Any thoughts on the rudder anode-to-skeg solution?

Bruce K [last name deleted for privacy by Editor]
- Bayonne, New Jersey

August 18, 2005

I too just got done replacing the outdrive on my 200 Maxum 2800. I keep mine in fresh water and replace the zincs and have the outdrive serviced religiously. A year and a half ago my buddy who is 2 slips down had to replace his so we had a mercury dealer come over and test to see if the marina was hot and everything came back fine. I'm now going to attempt to keep the boat unplugged when I'm not using it just to see if this helps. If anyone starts a class action please include me

Jeff M [last name deleted for privacy by Editor]
- Newcastle, Washington

September 10, 2005

I have a 2001 Bayliner with the Bravo III. Like everyone else have had nothing but problems with corrosion on the out drive. Of course the dealer sticks there head in the proverbial sand, and states that is my responsibility to protect the out drive. Like so many others, if there is a class action suit, please include me. Thanks

Steve B [last name deleted for privacy by Editor]
- Clover, South Carolina

September 12, 2005

I have the Bravo III on my 2000 Monterery. In 2002 (within my warranty period) I noticed chucks missing from the lower unit and other sections that crumbled between my fingers. My boat is meticulously serviced professionally. I was stunned to find these articles regarding corrosion.

I sent service/replacement requests to Mercruiser (Owner Warranty) and Mercury Product Protection (Extended Warranty) in an effort to get my I/O replaced.
April 25, 2002 I received a very handsome and informative package from Mxxxxx Bxxx of Mercury MerCruiser Customer Services that included among Mercruiser sale stuff, "marine corrosion protection guide" and a letter telling me that the Bravo III drive unit had NO corrosion issues. When I challenged this response, I received a second letter from Mxxxxx Bxxx, May 06, 2002, explaining that in addition to my original one-year, limited MerCruiser warranty, that there is also a 3-year corrosion warranty but corrosion was NOT COVERED.

I found the letters to be very confusing.
1) it denied any corrosion issues.
2) it stated that the problem is lack of owner preventive maintenance.
3) it stated that corrosion is not covered, even by the extended corrosion warranty.

My followup calls resulted nothing. Why are we, Bravo III owners, more stupid than any other boat owner? Does Mercruiser really think this way?

My authorized service dealer was told to sand, prime, repaint the lower unit, replace recommended zincs and added Mercathode. I paid for this several times adding thousands to my cost in the past few years.

I thought all was fine. And was thinking of upgrading to a larger boat. But this past Sunday, September 04, 2005 I was towed off the Potomac River My service guy just called to tell me that the I/O has corroded completely, blowing the entire lower unit. The cost to make the repairs on components that should last 10-15 years, a whopping $6,000.00. Oh, it gets better, my extended warranty expired 03/09/05.
My service guy is telling me that Mercruiser will not address the issue. Guess my new boat will use Mercruiser for an anchor only.

Class action suit, please include me!

Paul H [last name deleted for privacy by Editor]
- Manassas, Virginia

October 10, 2005

Hello everyone,

I have a 2001 Bayliner 2455 with this infamous Bravo III drive. After two seasons in the water (o.k. the water down here is pretty warm which speeds up chemical reactions, my outdrive is heavily corroded. I read in this forum that someone suggested to replace the B III with a B II unit and aluminum props. Has anyone tried this ? Before I start spending thousands on just another rotting drive, I'd rather put something different on this boat. I like the boat itself - just the drive drives me crazy. Any help is greatly appreciated. Thanks !

Michael H [last name deleted for privacy by Editor]
- Tuscaloosa, Alabama

October 12, 2005

I have a 98 Maxum 2700 that I just repowered from a 350 Bravo 2 to a 502 Bravo 3.With a single engine express cruiser the bravo 3 has improved thrust for planning and it is easier to dock.The top speed testing with the 502 using the bravo 3 is 48 mph and bravo 2 is 47 mph.Since I live in Florida along the coast and use the boat in Saltwater, most boat owners including myself have 3 choices to prevent corrosion and fiberglass blistering;lift storage,dry storage or trailer storage.Some marinas will allow you to install a lift.

A J L [last name deleted for privacy by Editor]
- Ormond Beach, Florida

November 2, 2005

I also have a 2002 Bayliner Ciera 2455 with a Bravo Three Drive. I keep the boat docked in the Housatonic River a swift moving current. Shore power is not available to us without running 250 of extension cords. After I purchased the boat new I heard stories of the Carrier Bearing corroding because of the electrolysis problems due to the stainless steel props. I immediately installed a second mercathode controller. At the end of the season when I pulled the boat my carrier bearing was severely corroded.
Mercury replaced the bearing with a newer version with some sort of coating under my warranty. At the end of the second season the same problem occurred but not quite as bad. To try and resolve the problem Mercury replaced the entire lower unit with their latest version, longer prop shaft with prop nut anode and double anodes on the cavitation plate.
When I pulled the boat this year no apparent corrosion appeared. It looks like this solved the problem in my case.

Edward B [last name deleted for privacy by Editor]
- Stratford, Connecticut

December 1, 2005

Hello b3 owners
I own a b3 x-drive with cummins diesel 2005, after 2 months in fresh water I had already a bit corrosion on the lower drive, reading all your problems I checked everything on the drive. I discovered that the mercathode not was connected to the battery, installed a second mercathode parallel to the other and checked the outlet voltage which was 4.2 volt in fresh water. The little corrosion/paint damage was repaired with epoxy paint. The boat (bl 275) has been in the water for 6 months. 2 weeks ago the boat was lifted out of the water, bottom and drive has been cleaned.The b3 drive looks like brand new.No corrosion, not even a spot. I am a happy owner now.

Rudi H [last name deleted for privacy by Editor]
- Holland

December 13, 2005

Here is a happier Bravo story.

I have an older Sea Ray that I repowered 3 years ago with a Bravo 3. When the job was finished my dealer had me sign a delivery inspection form from mercruiser and he also showed me some basic required maintenance that is listed in the owners manual. He really made a point to show me all of the things that should be done on a weekly basis. I was surprised to learn that all of the anodes must be inspected weekly. I have been doing that and having them changed twice during the summer and my outdrive is still in great condition. I keep my boat in Raritan Bay which is an oasis for corrosion. At the end of the season when all the boats are on blocks it is very obvious who maintains their boats properly and who doesn't. I did see several Bravo outdrives last month that were very corroded and each of them hardly had any zincs left. I'm probably a bit of a maintenance nut but I believe it's worth the effort.

The bottom line is that the Bravo 3 is more corrosion prone if there is not enough anode material to protect it. Also be sure to use the recommended aluminum anodes. My mechanic told me that the outdrives with the less expensive zincs usually corrode the fastest.

Bob S [last name deleted for privacy by Editor]
- North Brunswick, New Jersey

January 24, 2006

I'm in the process of buying my first boat. It's a used sea ray 300 sundancer with the bravo III drives. Since this is a newer boat than most of the ones that are having problems here, does anyone know if the problem has been fixed?

Gary C [last name deleted for privacy by Editor]
artist - Manhattan Beach, California

January 27, 2006

I would advise you to keep looking for a different boat. You are spending a "boatload" (sorry!) of cash on this boat, and if it turns out to be a nightmare of repair problems, you will end up spending more time at the mechanic's than out on the water. Is it worth the risk?

Stern drives are ill-suited for salt water. The e-ticket here in Florida is the salt water outboard, or a diesel inboard. I would look for something like that if you are going offshore. Stern drives are not the best choice for salt, even if there is not a corrosion problem with them.

Sea Rays are nice boats, but very pricey. I am not certain that the high price is justified by the quality of materials. There are better boats out there for less money.

You might get more bang for the buck elsewhere.

If you know about the Bravo III corrosion problem in advance, and still buy this boat, then you can't complain if it starts to corrode. If you do buy it, find a good marine mechanic and have it serviced every 3 months. If he electrical connections between the parts go south, it will corrode. The use of proper "zincs" and number and placement and proper operation of the mercathode system is critical. When it all works, it works great. When it goes south, watch out. Sort of like the Vega engine. It worked great in the lab....

Look at the outdrives carefully. Have they been replaced recently or are they starting to show signs of corrosion? Why is the previous owner selling? Did he have a corrosion problem?

I had a similar experience with Mercruiser customer service as the folks above with regard to my Bravo II drive. A little more than a year old, and the output coupler fails (only a $1500 repair). It seems odd to me that such a major driveline part should break so soon. But Mercruiser expressly does not warrantee the part, and blames the consumer for failure (I never had this sort of problem with my other outdrives....) claiming lack of lubrication and/or proper alignment (both factory tasks!).

Mercruiser blames the boat manufacturer for improper installation, and the boat manufacturer blames Mercruiser as it is a driveline problem. As noted above, they have a small army of "NO" people on the phone who right out of the box get all aggressive in your face. I e-mailed them initially to ask if this was covered and what I should do, and the initial response was almost angry. I was quite shocked. I guess they have a bunker mentality there.

Frankly, I'll never buy another US MARINE product again, in part because of the way Mercruiser's warranty people acted, but mostly because most of their products have the same quality level as American car manufacturers. There are choices in the marketplace, and you have to "vote" with your dollars (and sometimes you only get one vote!)

In my experience, the Mercruiser drives (Alpha I, Bravo II, Bravo III) need a lot of preventative maintenance - hauling the boat at least every 3 months for zinc replacement, and (in some cases) annual water pump replacement and seal renewal. I've had my Alpha I (Gen II) rebuilt twice so far, just as preventative maintenance.

My first boat had a 20 year-old Volvo Penta outdrive that was pretty bulletproof. Just change the 90 weight annually (and no special "mercfluid" is needed!) and it was always good to go, even in the salt. 20 years, and very little corrosion!

The new Volvo DuoProp has a composite casing, so it can't rust.

Brunswick/USMARINE owns about 60% of the boat market in the US (for the time being, anyway) and thus a majority of boats sold have Mercury or Mercruiser power. There was a big antitrust case on this a few years back. Brunswick owns both Sea Ray and Mercruiser. You'll only find Volvo Penta on non-Brunswick products.

As one mechanic told me, "There are lots of places to get a Mercruiser serviced, and lots of places to get parts. But, of course you need them. There are few mechanics that work on Volvo Pentas, but they rarely need work".

Japanese 4-stroke outboards are really starting to dominate the market. Predictably, Mercury went running to the government (International Trade Commission) and asked them to slap anti-dumping tariffs on the Japanese. The ITC refused, noting that the increase in sales was largely due to Mercury slapping japanese power heads on their lower units, painting them black and selling them as Mercurys.

You have to be careful when buying a boat. Remember the OMC FICHT fiasco? Boat owners who spend tens of thousands on high output FICHT 2-strokes found themselves with blown pistons - and no warranty coverage when the fiasco ultimately forced OMC into Chapter 11.

So choose wisely my friend.....

robert p [last name deleted for privacy by Editor]
- Pompano Beach, Florida

February 17, 2006

I just discovered your Bravo 3 problem/chat page.

I replaced the lower housing last season and I need to replace it again!

How do I get in touch with the people who are getting class actions against Mercruiser?

Thanks soooooo much!

Jan J [last name deleted for privacy by Editor]
e-mail: [deleted Mar. 2010]

Dear Reader: this thread is now "Read Only". Every flower goes to seed, and every discussion thread. is a site focusing on metal finishing; this thread started off related to metal finishing, and ran for 3 years, but now has nothing to do with metal finishing :-)
It's been fun! But we must focus our efforts on metal finishing, and there are boating forums more suited to where this thread has gone. Last names and email addresses were removed for privacy in March 2010.


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