Anodes

[PugetSoundBoater]

Here is what Marine Engine has for a 9.9. I always thought they were supposed to be Zinc. They list Magnesium and Aluminum also.
On all the used outboards i have bought that had anodes, they all had cast into them "Made In Canada". There must be big Zinc mines up there..Eh?
Any thoughts on this?

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson

[fleetwin]

Well, anodes have always been referred to as "zincs". But, usually, they are a combination of different metals, not just zinc. I’m surely no expert on the chemistry involved here, but it is all a matter of where the different metals fall on the chemical nobility scale. You want your anode to be a more "noble" metal compound than the various parts on the lower unit of the outboard or stern drive. Seeing an anode that is eroded away is a good thing, means it is doing its job trying to protect the lower unit. An anode that does not appear to be eroding at all means it is not doing its job, or is crusted over preventing it from doing its job. Needless to say, this is more of an issue in salt water than fresh.
None of this really answers your question I guess. I guess I might give the Sierra "zinc" anode a try, the OMC piece is priced a bit high. I don’t think I would take a chance on the Sierra piece that is marked "magnesium"…..

[Mumbles]

The aluminum anodes have been getting popular lately and I’ve heard they come as standard equipment on new Mercruisers now. I’ve used them the last two seasons on my Mercruiser but they didn’t seem to last as long as zinc ones. Part of that problem could be caused by other boats moored near me at the marina with worn out or no anodes on their outboards or sterndrives. Since the anodes don’t care whose boat they are protecting, I try and find a moorage spot near other boats which seem to be cared for and hopefully have good anodes on them. Magnesium anodes are for fresh water use only, not salt.

Martyr anodes, cast in Canada, are my favorites!

[PugetSoundBoater]

Just talked with a commercial plumber friend of mine. He said the anode in a water heater is magnesium or a mixture with magnesium in it.
So as Mumbles says, not that i doubted his info, magnesium is for fresh water.
I have a friend who is a retired commercial electrician,worked at a lumber mill on Puget Sound. I’m sure he will have some stories and info also.
Thanks, Jim PSB

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson

[billw]

Magnesium is definitely fresh water only. In salt water, the choices are only zinc or the aluminum alloy. I’m changing zincs all the time. It is my observation that the aluminum alloy does a better job of protecting what it’s supposed to protect; although they do deteriorate faster. Aluminum alloy (Mercury used to call it "Indium Aluminum, " if I recall right) is standard not only on ‘Crusier, but also on Mercury and Yamaha outboards. Do NOT use zinc in fresh water, as it will over protect and can bubble the paint. Zinc anodes will cause more corrosion in fresh water than if no anode was used at all.

Long live American manufacturing!

[vintin]

The less noble metal is going to be the one to lose material. Aluminum is more noble than magnesium and that is why it is suggested for aluminum boats and motors. If an anode has the same noble potential as what is desired to be protected then no protection results. If what is desired to be protected has a lower noble potential than the anode you’ve got a really bad situation where the anode stays in great shape while what you want protected corrodes away.

I’m just shooting from the hip here but if an anode corrodes away fast in a salt water environment, salt water being a highly conductive electrolyte, it seems to me that it is offering good protection.

I see Feather Craft boats with anodes that are sixty plus years old and still look good. My guess is they are offering no protection.

https://www.google.com/search?q=anodes+ … e&ie=UTF-8

[rmhxruss]

Look for a dealer that sells anodes from Canada Metals, Martyr brand. This company makes a lot of product for the OEM’s and is less expensive.

[PugetSoundBoater]

This is great info!
I will be looking for the Martyr brand with "Canada" cast into them.

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson

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