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Anode question..

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  • Anode question..

    I pulled the 3 anodes from my '06 F150 today, to check them.

    There are 2 in the head and one below the T-stat (port side)

    All had some salt build up reside on them but the lower, in the head, had a bit of pitting under the residue (no where's near replacing-just cleaning).

    Looking inside the engine, very clean.. The anodes cleaned up as well with a fine file and bench top wire brushing..

    Question, I know anodes are designed to sacrifice themselves over time.

    Why does salt residue build up on them?
    I gather the salt would interfere with how well they work?

    Feel free for discussion, Tks

    1997 Angler 204, Center Console powered by a 2006 Yamaha F150TXR

  • #2
    I believe once they get a coating covering the metal, they cannot do the job they were intended to.
    be it salt or other minerals
    pulling and cleaning or replacing with new would be a good Idea.

    what does you manual call for on those.
    at least they designed those to be pulled without taking the motor apart like you had to do on the old 2 strokes
    Last edited by 99yam40; 1 week ago.


    • #3
      I replaced all 3 many years ago (maybe 1/3 missing, still safe) and I saved one with little pitting.
      I used that "spare" which was in better shape than the lower one from this week.

      Inside the block, no crud/corrosion to speak of, just that covering of salt/sludge on the anodes..

      I agree cleaning them (as noted below) is a must, I was just curious as to why that coating developed.

      I just did a WP impeller/housing/LU oil change, pressure check, all seals inspection, (everything but wave washers) 11-17-21.
      The impeller needed changing, the rest in great shape, no corrosion. There was some sludge under the cover of the drive shaft (atop the seal)
      That cleaned out easily with water and a tooth brush.

      Next week I want to pull the T-stat and check under there (needs a new gasket so that's put off till then)

      Per the shop manual:


      F150 2.JPG

      Lower going back together:

      1997 Angler 204, Center Console powered by a 2006 Yamaha F150TXR


      • #4
        good question as to why the scale builds up on the anode but not the other parts in that area.


        • #5
          They are anodes, that means there is some electrical tension, that not only converts the metal to an oxide (attracts oxygen) but also attracts other stuff. You see this everywhere from inside batteries, coffee makers, pool chlorinators etc etc where electricity is present.
          I would not worry about it occurring as such, but the point about the need to replace them is that they become porous and convert to an oxide leaving less and less metal to participate in the process.


          • #6
            Thanks, makes sense.

            The lower, head anode is always the worst for some reason with "stuff" around the outside.

            A file and wire brush gets rid of it quick but you have to do some digging to get the actual oxide crud out..

            1997 Angler 204, Center Console powered by a 2006 Yamaha F150TXR


            • #7
              Some of you know Ole Parker. He has a nice shop in south Florida and is a Master Tech. He mentioned the scientific method of measuring an anode’s decline is by weighing before and after. Not realistic for most, but would be interesting. I have noticed that Yamaha keeps tweaking the composition of their exterior anodes over the last 10 years. Based on observation only! The straight zinc anodes apparently are toxic some claim and they seem more and more difficult to find at retail. Zinc anodes are noticeably heavier than AL and magnesium. I bought a Yam trim tab anode about 5-6 years ago and couldn’t visibly see any change over 6 months of using it. It was much lighter than straight zinc, obviously a AL blend. Replaced maybe a year ago with another (same) Yam part. It was a bit heavier and changed appearance quickly after the first run. Started eroding fairly quickly but not at the rate of a zinc part. That’s my unscientific observation. Hey, at least Yam is willing to adjust.


              • #8
                I’ll bet Yamaha are balancing cost, functionally and appearance. A good sacrificial anode turns “ugly” pretty quickly if it is doing it’s job.
                Weighing has it’s pitfalls (pun intended). It accumulates weight by adding oxygen to it, but this oxide also crumbles away (pits) eventually reducing it’s weight!