water leak , transom assy. replacement ?

[GCHOG]

Good morning all, hope everyone is staying safe / healthy. I'm looking for some advice / confirmation , suggestions, tips, etc. My '06 260 DA (6.2 BIII) had developed a slow water leak into the bilge early last season, ( boat is slipped during the season ). Checked all hose connections many times and determined a slow drip was coming from the transom assy. somewhere. After talking to some fellow boaters and looking at some post here, I believe I have a problem with a leak around the steering arm in the transom assy. I see some folks have done a complete transom housing assy. replacement and a few have gone the JR Marine repair kit route. I plan on keeping this boat for many more years, so I am not opposed to pulling the engine and drive and replacing the whole assy., I'm not gonna cheap out just to have the problem arise sometime in the future. So, I guess my questions are , I've seen a replacement assy. called "Seacore". Apparently built with SS parts as opposed to OEM steel parts. Has anyone had a Seacore installed and is this the best route to go ? I also plan on replacing the coupler, various hoses and any other related parts needed while I've got the whole thing apart. Any thoughts, suggestions, input, tips/tricks would be greatly appreciated. Thanks in advance !

Garry

 

[Ididntdoit]

I believe seacore has the stainless pin - so yes, I'd go with that - Smart to do the whole assy - you get all new bellows, lower cable, rams, mercathode, etc.....

 

[scoflaw]

4200 both sides of the foam rubber transom seal on assembly

 

[ColoSR]

I replaced my BIII transom assembly due to a leak as well. Using a replacement transom assembly cut down the time in the shop from 6 weeks to 1.5 weeks. The new assembly was about $3K and the labor to rebuild was about $2K, after getting it out the mechanic said that I saved money with new.

 

[Henry Boyd]

Good morning all, hope everyone is staying safe / healthy. I'm looking for some advice / confirmation , suggestions, tips, etc. My '06 260 DA (6.2 BIII) had developed a slow water leak into the bilge early last season, ( boat is slipped during the season ). Checked all hose connections many times and determined a slow drip was coming from the transom assy. somewhere. After talking to some fellow boaters and looking at some post here, I believe I have a problem with a leak around the steering arm in the transom assy. I see some folks have done a complete transom housing assy. replacement and a few have gone the JR Marine repair kit route. I plan on keeping this boat for many more years, so I am not opposed to pulling the engine and drive and replacing the whole assy., I'm not gonna cheap out just to have the problem arise sometime in the future. So, I guess my questions are , I've seen a replacement assy. called "Seacore". Apparently built with SS parts as opposed to OEM steel parts. Has anyone had a Seacore installed and is this the best route to go ? I also plan on replacing the coupler, various hoses and any other related parts needed while I've got the whole thing apart. Any thoughts, suggestions, input, tips/tricks would be greatly appreciated. Thanks in advance !

Garry

You seem to have gotten bad information. The Bravo III transom assembly is primarily aluminum (cast?) with steel components made with stainless. I do not know about the Seacore versions, but I would be greatly surprised if the major components were made with stainless because of cost, weight, and fabrication. Further, making the transom assembly would exacerbate the galvanic corrosion issues with the drive housing that are still aluminum.

My understanding is that Seacore is primarily the use of better coating materials to prevent corrosion.

 

[Spark600]

You seem to have gotten bad information. The Bravo III transom assembly is primarily aluminum (cast?) with steel components made with stainless. I do not know about the Seacore versions, but I would be greatly surprised if the major components were made with stainless because of cost, weight, and fabrication. Further, making the transom assembly would exacerbate the galvanic corrosion issues with the drive housing that are still aluminum.

My understanding is that Seacore is primarily the use of better coating materials to prevent corrosion.

I have Seacore drives as stated above a layer of corrosion prevent material inside and out, all hardware is all stainless steel with shower drives.

 

[Henry Boyd]

I have Seacore drives as stated above a layer of corrosion prevent material inside and out, all hardware is all stainless steel with shower drives.

From Mercruiser parts web page, a description of the components in the Seacore drives:

https://www.mercruiserparts.com/seacore-system

“The heart of the corrosion-resistant strength of the SeaCore System is the hardcoat anodizing of the drive alloy. This process actually changes the molecular structure of the XK-360 aluminium alloy, creating a shield against the ravages of galvanic corrosion. Hardcoat anodizing is also more abrasion resistant than case-hardened steel, but if the drive is scratched, the anodizing slows the destructive growth of corrosion through the drive surface.”

As an FYI, anodizing is the process of electrically inducing Galvanic corrosion Of the aluminum to create a layer of aluminum oxide. Aluminum oxide is indeed very tough, but in a virgin state, porous And not very strongly attached to the base metal. It can also easily scraped off by mechanical abraision. However, an oxide layer on aluminum is different than the oxide on steel. Once established, the aluminum oxide layer retards additional corrosion. Unless the base metal is exposed corrosion is halted.

Chemicals are used to seal the the porosity to toughen the surface. Because of the porosity, dyes included in the sealing process can create very durable colored coating. Once sealed the anodizing creates a very strong corrosion barrier.

So in a nutshell, the basic Bravo Three is painted aluminum, the Seacore drive is anodized aluminum. When I was checking my facts, it seems to me the Seacore concept has been dropped by Merc. Anyone have any news on that?

 

[GCHOG]

thanks everyone for your input. Henry, I know the transom assy. is made of cast aluminum, in my original post I was meaning that some of the parts ie;steering arm and pin were SS not the whole casting. Thanks for the info regarding anodizing, very helpful. I actually spoke to a Tech at Mercruiser yesterday regarding the differences between the basic BIII drives and the Seacore drives and was told the difference between the two is the coatings that are used, same as you said. His advice was that I really don't need the Seacore assy. since i don't have a OE Seacore drive, however it wouldn't hurt anything. That said, I'm still on the fence on which assy. to get. I like the idea of the SS steering arm and pin along with the other harder coatings on other components.
I slip the boat in a fresh water river marina, so salt water corrosion is not a big concern. I do boat out to salt water area's but when I return it basically gets flushed out.
I would still appreciate anyone's input , the more info ,the better.
Hope everyone has a safe, happy Easter weekend !

 

[Henry Boyd]

GC,

The B3 I replaced had been in salt water and it was aluminum that failed from the inside due to corrosion. I dismantled the old transom assembly (vintage 2002) and found that all steel on the outside was stainless. The steering pin is stainless. As for the steering arm, attaching bolt&nut, and mounting studs while not stainless only had surface/cosmetic corrosion.

Our transom assembly failed because the raw water feed for the engine rotted out where the raw water flowed through the assembly. Basically the casting around where the raw water hose adapter attached to the inner transom plate corroded to the point where the two bolts simply could not hold the adapter in place.

Here are some photos:

This shows the exterior plate and the through transom mounting studs. The studs look nasty, but it was all surface.

Here is a close up of where the raw water hose mount.

My suggestion on the “to Seacore, or not to Seacore,” question depends on a few things. First, how long are you planning to keep the boat? What is the price differential between the two? Are you willing to absorb the loss from not being able to recoup the difference if you do sell?

First, my experience both as a recreational boater, and as a marine engineer tells me the Seacore is better than the standard design. The big question is will it pay off for you? You also have to recognize that you will get very little on resale for having the Seacore. My experience when we sold the 280 was that having replaced the transom assembly helped, but the big plus was the brand new exhaust manifolds and water pump.

 

[El Capitan]

Is this more common to the BIII or are all the drives subject to this?
Makes me reconsider my alpha in salt water.

 

[scoflaw]

You don't need the sea core but the pin is a better quality SS than the regular assembly has. You can buy a top tier pin for about $100 online. Me, in your situation, I'd buy the regular TA and change out the pin.

 

[Henry Boyd]

Is this more common to the BIII or are all the drives subject to this?
Makes me reconsider my alpha in salt water.

Any aluminum in salt water is going to be at risk. The alphas are less at risk because there is limited steel in proximity to the casing (assuming alu prop) than with a B3. In your case the good news is if you store your 180 on land, or a lift in Florida the risks are significantly reduced.

 

[BillK2632]

Is this more common to the BIII or are all the drives subject to this?
Makes me reconsider my alpha in salt water.

Alpha's tend to fair better in salt water -

• They don't have the duoprop, so that reduces the corrosion due to galvanism.
• They are not nearly as big and heavy, so wear on the stearing pin is much less.
  • My BIII was starting to steer sloppy and leak after 5years - my alpha is 20yrs old and still dry and tight.
• The water pump design with the impeller in the outdrive pushes water into the engine vs pulling it like an engine mounted pump. Have to remove the drive to service, but a better pump in my opinion. They don't seem to suffer the "bravoitis" cooling issue. Mercruiser could take a queue from Volvo on the pump design.

 

[Henry Boyd]

You don't need the sea core but the pin is a better quality SS than the regular assembly has. You can buy a top tier pin for about $100 online. Me, in your situation, I'd buy the regular TA and change out the pin.

What is “better quality”? BTW, “better quality” is a meaningless term in the engineering context you are using. “Quality” simply means adherence to a specification. What quality are you referring to? Tensile strength? Elongation? Ultimate strength? Alloy content? What specifically? Do you even know, or is it just because it says so on the label, or that it costs more money?

Does the “better quality” translate to money savings? What is the savings mechanism? How much money is saved? Over how long a period?

Do the “savings” offset the premium cost of the part, loss of warranty on $4k transom? The $400 to $700 more to strip down a brand new assembly and put it back together again?

 

[scoflaw]

304 compared to 316. The difference between the regular and sea core pin. $400 to $700 to replace the pin on a new assembly? Really ? Oh yah, I forgot, you don't turn wrenches LOL

 

[b_arrington]

You don't need the sea core but the pin is a better quality SS than the regular assembly has. You can buy a top tier pin for about $100 online. Me, in your situation, I'd buy the regular TA and change out the pin.

This is what I would do. IMO unless the price differential is small, it’s likely not worth the extra cost. I recall that the original upcharge for SeaCore was very substantial - prohibitively so.

The point of failure in the steering pin is the non-stainless steel material. It corrodes and then tears up the pin seal. That lets water in the boat and drips down the inside of the transom. Stainless pins stay smooth and the seal stays intact.

 

[scoflaw]

The reg. assembly pin is a cheap grade of stainless, not just a steel pc. Merc wants big bucks for the seacore pin.
I've had good luck with the ebay pins from well known marine outlets.

 

[Henry Boyd]

304 compared to 316. The difference between the regular and sea core pin. $400 to $700 to replace the pin on a new assembly? Really ? Oh yah, I forgot, you don't turn wrenches LOL

Exactly, why is 304 different than 316?

The reg. assembly pin is a cheap grade of stainless, not just a steel pc. Merc wants big bucks for the seacore pin.
I've had good luck with the ebay pins from well known marine outlets.

Ah, the old capitalistic conspiracy school of non-engineering. "The evil capitalist wants to screw me". You mean the manufacturer who will warranty the $ 4000.00 part unless you try to prove you are smarter then all of their experience and engineers by installing your own cut rate eBay sourced parts? So how are you smarter that Mercury Marine? Have you been a marine technician? Marine engineer? Engineer of any kind? Machinist? Do you have any skill or training that makes your position valid, or supports the cost - benefit? Other than low price, which seems to be a recurring theme in your M&R suggestions, what makes the difference?

If Mercury sells "cheap steel", how is a bargain basement eBay sourced pin any different? Are you getting a mill cert? I'm also not sure what you mean by cheap. Are you claiming Mercury sells parts as meeting one standard, but they are selling something else?

As for spinning wrenches. Again I know how to, I care not to.

And by the way, you didn't answer my question. If you choose to regurgitate the stock google answer, please be prepared to explain why the composition of an Austenitic stainless is significant and why the difference makes it a better engineering choice? Other than its not cheap steel? BTW neither 304 or 316 is cheap.

You can find the answer in a Marks handbook, La Que & Copson's "Corrosion Resistance of Metals and Alloys", or even the rather simplistic "Corrosion Engineering" by Fontana & Green.

The point is other than "you think" and the unsubstantiated opinion that Mercury sells "cheap steel", you have nothing to justify spending several hundred dollars, or many hours of labor. In point of fact, you have not even done this type of thing on your own boat. So you don't even know if it will work at all.

 

[ColoSR]

You have to look at the whole system, one piece can be a weak link but it’s not going to provide outsized protection either. The stainless steels are subject to chloride pitting corrosion, rule of thumb for SS piping is that 304L is good for up to 100 ppm chlorides while 316L is good up to 2,000 ppm. Freshwater is generally less than 100 ppm chlorides, brackish is 1,000 - 3,000 ppm, and saltwater is 35,000 ppm.

That being said, your drive has dissimilar metals in contact with one another and both 304L and 316L are far more noble than aluminum so you will more likely see general corrosion of your aluminum long before you see pitting corrosion of the stainless steel. For longevity, I would focus on (1) keeping your anodes & mercathode system in good shape, (2) keeping paint on the aluminum portions of the drive, (3) limiting biofouling, then looking at materials of construction.

It was an extra $400 + 2 weeks delivery for sea core when I replaced my assembly. Boat spent the first half of its life in Florida, so had more corrosion than we typically see in Colorado. I also had to replace the coupler, u-joints, half of the drive shaft, and a motor mount in addition to the transom. Fortunately for me the transom wood was still intact enough that I didn't have to send it to the body shop (additional $6K).

 

[ColoSR]

I forgot, the corrosion warranty on the standard unit is 3 years, sea core was 4 years. Parts and labor warranty from mechanic was 1 year. Non-merc parts voids the warranty.