Corrosion/electrolysis around engine anodes

[Innovator33]

I have been noticing over the past 12 months or so an accumulation of "powdery" looking deposits forming around the gasket line of the plates that the engine anodes are fitted to. This is a Yanmar 2QM20, raw water cooled engine. These powdery deposits are only on the joins where the anodes are, not on any other bolt on plates. The anodes will be down to about 40% after 2 years, and this rate of erosion has not changed. I have not altered the electrical system in any way lately; the shaft anode erosion has stayed constant. I am on a swing mooring so no vessels nearby.
The pictures show what the anode looked like when removed. The engine/head metal is still solid with no indication of wasting. The powder is very similar to what you see on the terminals of a battery.
Should I be worried? Or are the anodes doing exactly what they are supposed to do - sacrifice themselves?
The electrolysis/power cleaned off easily, and I fitted a new anode and refitted it all.
Thanks
Michael

[tkeithlu]

"gasket line of the plates that the engine anodes are fitted to."

These anodes are grounded to the engine, right? Assuming that, they are doing their job and you can move on to the next problem. Hey, you noticed and came to ask. It's the owners who don't see such things who need to worry.

[DougR]

Often called salt creep, it doesn’t seem to hurt anything. It’s probably calcium carbonate precipitating out and leaching thru the gasket surface. You see it on salt water cooled engine blocks, seawater cooled oil coolers, heat exchangers, etc.

[Compass790]

All is normal re anode but your gasket is leaking a tiny amount. Best to use a thin smear of silicone on both faces & let it go off before you install the gasket I have found. Don't know how much your 2QM20 vibrates but if its anything like our YSM8 you need to use threadlocker on the bolts as well.
This method worked for me to stop the salt creep.
If you keep your boat at a dock with fresh water available its a good idea to put a tee & valve in the water intake hose & flush your engine after use to extend anode life if you wish. Probably extends block life & lessens buildup in cooling galleries as well. Use a hose from the tee with into a bucket of fresh water to suck fresh water up into engine whilst its running & water intake seacock is turned off.
Dont forget to shut valve on tee after you have flushed it.

You can probably put a water hose into the tee but you need to get the pressure right I imagine. I havent done it that way.