Inspecting/Replacing Yanmar Engine Anodes

[Guest]

I want to remove the engine anodes on my raw water cooled Yanmar 2GM 20.There appears to be some sort of bedding compound around them.Do I need to get some bedding compound and if so what is it called?Also what should I be looking for when I remove them so as to know if they need replacing?

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[snowleopard]

there was a long thread about this recently, try a search.

don't use ptfe tape or anything that might insulate the plug from the block. plumbers 'Boss White' would do the job.

compare your anode to a new one, if less than 50% of the volume, replace it. otherwise scrub and replace.

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[paulrossall]

I have done mine today on identical engine. They have been in for about 200 hours running and are less than 33% worn. I do not use, and in my opinion you should not need to use, any sealing compound. If you insulate the anode from the engine it will not work. As previous post says get new ones, you will need them sometime and compare them to the ones you have in. I seem to remember one has a funny rubber gromit type thing on it but the other does not. If in doubt ring Barrus the agent and ask their technical people. I have found them helpful in the past and if they are not responsive let us all know.
I have standard Yannmar mounts, a standard coupling from gearbox to shaft (not flexible) a stuffing box and the prop shaft protrudes out my skeg keel. I am noticing the shaft vibrates more than I would expect. Boat is a Macwester 30.
What type of boat do you have and what couplings etc. do you have? I think that maybe I need a flexible coupling but I am concerned that maybee my mountings are worn. They are 10 years old but engine has only done 1000 hours.
Regards.Paul

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[johnt]

Yanmar anodes that look ok after a long period of service are porous and heavily fouled with lime..........for the low cost of replacing. it isnt worth messing about with them.

For the doubters ...... I put two old anodes in brick and tile cleaner, they both seemed to be nearly perfect. 24 hours later they where still fizzing. At the end they still looked pretty well ok for shape but where visibly porous...so the 1/3 loss dosn't just come off the outside. CHANGE THEM ANYWAY!

John

PS ...and I have photos to prove it



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[snowleopard]

what's in your brick cleaner? almost certainly some sort of acid which would attack zinc! i suspect that's what has eaten the anode. to test, collect the gas and set light to it, if you get a 'squeaky pop' it's hydrogen.

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[johnt]

its Hydrochloric acid and it attacks limescale a lot more vigorously!..........so the exercise stands! ...
The anodes are porous!.........as my shaft anode usually is when I change it !

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