replacing the lower two anode bolts on Mercruiser transom assembly

[Fishermark]

I am replacing the two lower anode bolts on the transom assembly of my 86 Welcraft with an Alpha drive. (They are pretty corroded up). My question concerns the two rubber washers. Do they go between the bolt and the transom assembly? That would make sense... but they would need to really stretch over the square area and become pretty distorted.

Let me know. thanks!

 

[tank1949]

I am replacing the two lower anode bolts on the transom assembly of my 86 Welcraft with an Alpha drive. (They are pretty corroded up). My question concerns the two rubber washers. Do they go between the bolt and the transom assembly? That would make sense... but they would need to really stretch over the square area and become pretty distorted.

Let me know. thanks!

In my opinion, that is another MC design screw up. They don't use them anymore. I guess cause too many boats SUNK! I had an 86 Sea Ray AJ with that crappy anode design. Local MC dealer in the early 90s agreed with me. I replaced with ss bolts and lots of 5200. After one motor hydro locked due to a head rusting out internally. I pulled 2 of them on each of my MC v8s and replaced with ss. Good luck! Just be sure you have anodes elsewhere.

 

[Fishermark]

Well, I have them and will probably use them... I thought of using some 5200 on them and may do it. I would be concerned with using stainless there as it would tend to eat up the housing I would think.

 

[Rick Stephens]

I think they use aluminum there for lower shear strength to act as a shear bolt if you hit something. They did go away from that in later models. Last time I did an aluminum one the rubber washer had a square hole and went on the outside, of course. Like tank, I 5200'd the crap out of the hole.

Rick

 

[tank1949]

Well, I have them and will probably use them... I thought of using some 5200 on them and may do it. I would be concerned with using stainless there as it would tend to eat up the housing I would think.

If my memory serve me, I replaced with carriage bolts that went all the way through transom and use a large finder washer/ss nut on the inside of boat with lots of 5200. The outside had the smooth ball finish. Local dealer didn't have a problem with ss, in fact he told me about it and sold me the stuff. BUT, I never stored boat wet in salt water. Good luck!

 

[nola mike]

Just doing mine as well. For what they charge those things should be made of unicorn horns. I'll be the dissenting opinion here. I'm going to 4200 the crap out of the holes. Those washers looked like very little protection.

 

[59Thompson]

The anodes have that recess for the rubber washer is what I have been told to enable them to conduct current but still be able to be removed.

 

[achris]

Yes, rubber washer goes under the anode. Any good NON-HARDENING sealer on the bolts is a good idea. And also yes, SS will promote corrosion of the housing. Easier and cheaper to replace a couple of bolts than the entire housing...

tank1949 How do these anodes and bolts cause engine heads to corrode out? I don't see any connection (literally!)...

Chris...

 

[tank1949]

Yes, rubber washer goes under the anode. Any good NON-HARDENING sealer on the bolts is a good idea. And also yes, SS will promote corrosion of the housing. Easier and cheaper to replace a couple of bolts than the entire housing...

tank1949 How do these anodes and bolts cause engine heads to corrode out? I don't see any connection (literally!)...

Chris...

Salt water environment caused heads and anode bolts to cancer! I pulled both and saw the cancer. Water jacket eaten through. My original 86 was stored wet in salt water before I bought it in early 90s. Local MC repair shop instructed me on ss carriage bolt replacement over POS MC design. I NEVER had issues with ss carriage bolts. I sold boat in 2000/1.

 

[Rick Stephens]

Just doing mine as well. For what they charge those things should be made of unicorn horns. I'll be the dissenting opinion here. I'm going to 4200 the crap out of the holes. Those washers looked like very little protection.

I think you are right about using 4200. Now that I think about it, I would have used 4200 and not 5200 for sure. I filled all available space and wiped off the excess. Same as you.

Rick

 

[GA_Boater]

Salt water environment caused heads and anode bolts to cancer! I pulled both and saw the cancer. Water jacket eaten through. My original 86 was stored wet in salt water before I bought it in early 90s. Local MC repair shop instructed me on ss carriage bolt replacement over POS MC design. I NEVER had issues with ss carriage bolts. I sold boat in 2000/1.

Did you have any anodes left?

Ditto on 4200 instead of 5200 if you ever have to remove the bolts.

 

[achris]

Salt water environment caused heads and anode bolts to cancer! I pulled both and saw the cancer. Water jacket eaten through. My original 86 was stored wet in salt water before I bought it in early 90s. Local MC repair shop instructed me on ss carriage bolt replacement over POS MC design. I NEVER had issues with ss carriage bolts. I sold boat in 2000/1.

What a load of ..... !

The only reason you're going to get those sorts of problems is if the maintenance and attention to MerCruiser's corrosion resistance items are completely neglected. Those lower gimbal housing bolts and anodes are fine and DO NOT 'cancer' unless the anodes have been completely depleted and then not replaced. The 'local MC repair shop' is an idiot, and for suggesting replacing those bolts with SS, should have his dealership agreement cancelled for doing things that will cause more problems than they solve, and potential landing Merc in court.

I can't stress enough. DO NOT USE STAINLESS STEEL BOLTS IN THE BOTTOM OF THE GIMBAL HOUSING. Use the bolts and anodes MerCruiser intended...

Tank, discussion over! Further comments to the contrary may be deleted. In these forums, we follow best practices (and manufacturer's recommendations) not fly-by-night maybe fixes...

Chris....

 

[tank1949]

Deleted. Argumentative and unhelpful.

 

[fbeck01]

View attachment 317333
I am replacing the two lower anode bolts on the transom assembly of my 86 Welcraft with an Alpha drive. (They are pretty corroded up). My question concerns the two rubber washers. Do they go between the bolt and the transom assembly? That would make sense... but they would need to really stretch over the square area and become pretty distorted.

Let me know. thanks!

I just took mine off, I see lots of people have replied and the rubber washer directly in front of the anode. I can't find the rubber washer though, what part# did you use to find them? I'm curious how you replaced these? I have a Murcruiser 3.0 4 cylinder and I cannot get to the bolts, I think I'd have to pull the entire engine to get to everything. I'd love to know how you did it?

 

[fbeck01]

Just doing mine as well. For what they charge those things should be made of unicorn horns. I'll be the dissenting opinion here. I'm going to 4200 the crap out of the holes. Those washers looked like very little protection.

I just ended up doing the same thing, only I've used 4200 around not just the bolts but also the entire housing (not sure what its called) because of a leak. I'm curious how well yours held up after you used the 4200 on it, if at all or how long? Photo of where mine was leaking, red leak dye to find the leaks - now sealed using 4200, pending drying and testing

 

[fbeck01]

I think you are right about using 4200. Now that I think about it, I would have used 4200 and not 5200 for sure. I filled all available space and wiped off the excess. Same as you.

Rick

Rick, how did the 5200 hold up sealing those Anode through bolts? I am just going through the same thing on my 1999 Sea Ray. I've used 4200 on mine. Would love to know if it's held up for you?