Salt Water Corrosion, Time to bust out big BOAT dollars...

[ChuckW]

For those that know me here, like so many of us on this forum, I take pride in taking good care of my boats. Always do scheduled maintenance, always tackle problems when they occur, try to be pro-active. Do projects that I can and hire a mechanic when I can't. I've got 6 full seasons on my 260DA and 671 hrs. The past couple of years I've had my mechanic pull the elbows and inspect risers and elbows. They look great and continue to. Just found why though. They are stainless steel and not indicative of where my corrosion is really at. And thus this winters project is now huge. On top of keeping an eye on it, this past season I had a water leak show up and in my last outing had some overheating occur, http://clubsearay.com/showthread.php/56511-Overheating-or-just-the-circumstances-of-the-moment , I guess the seaweed wasn't the real cause after all. So I sent it in to have a full inspection, cleaning and maintenance done. Hoping for the best but knew deep down there would be work to be done. Boy was I in for some surprises on this one.

Engine block exhaust port...got lucky we found this in time.


Freeze plug hole completely blocked with corrosion


FSM coming apart...


Exhaust manifold failed


Wire harness melted....


Steering pin destroyed, source of water leak...arggggg


Transom plate shot


Tubeits ocluded...


Y-pipe, time for a new...



So the engine has been pulled out, other than elbows and risers (still pristine), I'm putting in new exhaust system and transom plate. Ouch....

I figured the exhaust was due for replacement, but never saw the steering pin problem and resulting need for a transom plate coming.

Hey, it's a boat, and we boat lovers love writing checks...

Cheers,

 

[Quint4]

Very good write up....with great pics! Sorry about the trouble. This ones gonna sting a bit.

 

[Jimmy Buoy]

Chuck, sorry to hear of your corrosion issues. Wow! At least your year boat had cast iron manifolds. The older 8.1 aluminum ones would have probably destroyed your engine long ago. Thankfully it appears that you've gotten to it before destroying your exhaust valves.

Often we think it's better to keep our eyes shut and trust that things are ok. This definately proves that to be incorrect. (more like pay a little today, or a lot more tomorrow)

I sadly just got back from a week in Ft. Myers, but will be returning in two weeks for the balance of Feb. It's definately a great spot for boating this time of year.

Good luck with getting all the repairs done as quickly and painlessly as possible!

 

[themikehyde]

I had to replace my starboard transom assembly last spring due to a worn steering pin. The port side was fine. Its nice knowing all that is new. Have had a bone dry bilge ever since.

 

[kevin27]

Sorry to see that. No suprise though as I had to replace my transom assys too on my 300DA. Bravo 3 and saltwater is just bad. Are you replacing the engine too? Looks like the cooling passages are blocked with rust. Here was my repair.http://clubsearay.com/showthread.php/53822-Bravo-Three-Transom-Replacement

 

[ChuckW]

Sorry to see that. No suprise though as I had to replace my transom assys too on my 300DA. Bravo 3 and saltwater is just bad. Are you replacing the engine too? Looks like the cooling passages are blocked with rust. Here was my repair.http://clubsearay.com/showthread.php/53822-Bravo-Three-Transom-Replacement

We caught it before it got to the engine. They are going to clean it all up good. I looked at your pix...very similar condition on the transom assy. Your tubeits was even more choked off then mine. Its a wonder you could get any water through there at all.

I'm hating outdrives...looking forward to an upgrade to straights one day

 

[Dave S]

Sorry to hear about your problems Chuck. Hope the bill isn't too high.

Dave

 

[kevin27]

We caught it before it got to the engine. They are going to clean it all up good. I looked at your pix...very similar condition on the transom assy. Your tubeits was even more choked off then mine. Its a wonder you could get any water through there at all.

I'm hating outdrives...looking forward to an upgrade to straights one day

I sold the boat 2 months later for that same reason. Love the straight drive inboards!

 

[ChuckW]

Sorry to hear about your problems Chuck. Hope the bill isn't too high.

Dave

Thanks Dave....been a while. Good to hear from you.

Chuck

 

[fwebster]

A man only wants to experience the "Mercruiser Corrosion Perfect Storm" that simultaneously gets cooling, exhaust and outdrive parts once in his lifetime..............I'd be considering alternatives to this boating thing that don't involve outdrives.

 

[ChuckW]

A man only wants to experience the "Mercruiser Corrosion Perfect Storm" that simultaneously gets cooling, exhaust and outdrive parts once in his lifetime..............I'd be considering alternatives to this boating thing that don't involve outdrives.

I haven't found a trailerable Sundancer with straights yet...If I do I'll be sure to let everyone know.

 

[KP49]

Wow that swivel pin/steering arm is pretty nasty looking.

Mine only spent a couple years in salt water and the swivel pin was rusted and the seal was completely gone, the water inlet looked similar to yours though, once that salt gets in there even sitting in freshwater for a couple years doesnt rinse it out. I was able to save the transom plate and not pull the engine so it wasnt that bad money-wise. I can imagine thats going to cost a ton just in parts, salt water is tough on them for sure.

 

[Big Island Lifer]

Not to pour "salt on the wound" but this is why Sea Ray is looking to outboard motors for a possible option for cruisers.


Sent from my iPhone using Tapatalk

 

[ZZ13]

I have two questions. Ben several threads/post on this failure over the years. So, how exactly does salt water get at the swivel pin? Are not all the internal metal parts sealed off from water exposure?

Second question: Would converting to through hull intake for the BIII seawater pump and sealing off in the lower unit intake eliminate the chance of exposing the swivel pin and other BIII internals to salt water?

 

[KP49]

I have two questions. Ben several threads/post on this failure over the years. So, how exactly does salt water get at the swivel pin? Are not all the internal metal parts sealed off from water exposure?

Second question: Would converting to through hull intake for the BIII seawater pump and sealing off in the lower unit intake eliminate the chance of exposing the swivel pin and other BIII internals to salt water?

The salt water can get at the swivel pin/seal when the drive sits low in the water like many cruisers do, that plus most cruisers sit in the water all the time. When on plane the pin is above the waterline. Most bowriders the seal is above the waterline so even if it did fail you wouldnt see a lot of leakage. Problem is the pin rusts, then it either tears up the cheap little seal. In my case both the pin rusted and the metal shell of the seal rusted away. With no seal at all left if sitting in the water overnight it would maybe have a gallon in the bilge, since I keep mine on the lift and it was in fresh water it wasnt a big issue for me, it would take a week of sitting in the water before the bilge pump came on so a lot of people probably dont even notice it. As corroded as everything was on mine the upper bushings were still fine and I was able to save most of the parts. Another thing with mine was the aluminum lower swivel pin has some kind of hard anodizing on it and salt got behind it and blew it up in size, tore up the lower fiber/plastic busing on the gimbal ring pretty good and I had to replace that as well.

It has nothing to do with the water intake, but if I had a big block I would be looking at an underwater stainer/pickup anyhow, even unobstructed the little intake hose with the insert is barely enough to feed the raw water pump.

Its one of those issues where you are better off being proactive and fixing it before you start seeing leaks or water pressure dropping, there is no doubt in salt water the pin is going to rust and the water inlet hole is going to start corroding and closing up on the intake hose. I used a stainless upper swivel pin on mine, the OE one will rust again, there is also a kit out there that uses a stainless steel pipe for the water inlet so if your transom plate is opened up where the OE hose/insert no longer works you can save it. It still amazes that three years of fresh water use after only two years of salt water use (on a lift) how corroded everything was and how much salt was still packed in everywhere on the transom plate. Right before I bought the boat Mercury replaced the drive due to corrosion issues, they really should have replaced the entire transom plate/gimbal ring/bellhousing also.

 

[ZZ13]

Thanks KP. So is what you are saying is that these are designed such that water naturally is allowed to fill up the upper unit?

 

[KP49]

Thanks KP. So is what you are saying is that these are designed such that water naturally is allowed to fill up the upper unit?

Not sure what you mean by fill up the upper unit, they can be completely submerged to the top of the transom plate if thats what you mean. Some boats the swivel shaft seal will be above the waterline just sitting in the water, others it will be underwater. When the shaft rusts and seal starts failing the ones that sit under the waterline are the ones that will leak naturally.

On the older drives the gimble ring u-bolt could stretch as well and the upper swivel shaft could wobble around and take out the seal as well as wear out the gimbal ring so its not just the unlucky salt water guys. Then there is also the shift cable and driveshaft bellows that can leak water into the boat, same with the grommets on the trim sender wires, o-ring on the distribution block for the trim hoses, intake hose, the tube for the lube monitor can leak too. When you look at all those points water can come in its amazing they dont leak more.

 

[ZZ13]

We're almost home KP, bear with me. So, the swivel pin rusts and then the rust defeats the seal which in turn starts the leaking process. I think I got that part understood. So the genesis of my original question is: Why does the steering pin rust? Is it not in an enclosure protected from the water (even when the unit is fully underwater)? Seems like since you have to pull the engine to get at the pin from the inside, or get a kit that lets you cut a hole to get at the pin (and then reseal the hole), that water by design should not be getting at the swivel pin to cause it to rust even when the drive is fully submerged.

 

[KP49]

The lower part of the swivel pin is wide open and exposed to water, only the upper part on the other side of the seal isnt directly exposed to water. Thats why you have to remove the engine or cut the hole to remove the top nut and steering arm from the swivel pin. The first pic in this thread is what my upper swivel and seal looked like:

http://clubsearay.com/showthread.php/55026-2007-Bravo-swivel-shaft-seal-leak-opening-a-can-of-worms

I tried to clean up the pin in a lathe but once I got to the point of no more pitting where the seal rides it was way too small, was going to try a stainless sleeve but for what the new stainless pin cost I figured why mess with it any more. On mine the main failure was the metal seal body itself actually rusted away, the seal was nothing but an o-ring when I took it out. Of course if the shaft wast rusty and let a little saltwater by first the seal the seal itself wouldnt have rusted away.

It rusts because it is carbon steel of some sort, new they may have some kind of ant-rust coating, I replaced mine with an aftermarket stainless pin. The marina that I asked about repairing mine refused to use the stainless pin, only would use OE merc parts so thats why I ended up doing it myself. Even though I'm not in salt water the stainless pin was 100.00 cheaper so why worry about it rusting again.

 

[ZZ13]

The lower part of the swivel pin is wide open and exposed to water, only the upper part on the other side of the seal isnt directly exposed to water. Thats why you have to remove the engine or cut the hole to remove the top nut and steering arm from the swivel pin. The first pic in this thread is what my upper swivel and seal looked like:

http://clubsearay.com/showthread.php/55026-2007-Bravo-swivel-shaft-seal-leak-opening-a-can-of-worms

I tried to clean up the pin in a lathe but once I got to the point of no more pitting where the seal rides it was way too small, was going to try a stainless sleeve but for what the new stainless pin cost I figured why mess with it any more. On mine the main failure was the metal seal body itself actually rusted away, the seal was nothing but an o-ring when I took it out. Of course if the shaft wast rusty and let a little saltwater by first the seal the seal itself wouldnt have rusted away.

It rusts because it is carbon steel of some sort, new they may have some kind of ant-rust coating, I replaced mine with an aftermarket stainless pin. The marina that I asked about repairing mine refused to use the stainless pin, only would use OE merc parts so thats why I ended up doing it myself. Even though I'm not in salt water the stainless pin was 100.00 cheaper so why worry about it rusting again.

Great explanation. Thanks. I can see in the finished picture in your thread where the bottom of the pin is. Does the fact you have a little stainless steel piece there (the bottom side of the pin) add any further concern about more dissimilar metals underwater? My whole reason for these questions was to hone in on whether anything preventative could be done to either eliminate or lengthen the time for failure in salt water. The SS pin looks like the only option. I guess there probably isn't room to custom make/bond a "cover" over the underside of the pin to completely seal it off from the water.

Thanks again for the explanation.