Engine Anode Condition

[CaspersCruiser]

I’m changing all the anodes on my Yanmar-powered 2012 R27. Except for a 10-day Florida Gulf Coast cruise in February, the boat has been operated in fresh water since I took possession about this time last year.

Below is a photo of an engine anode. I have zero experience evaluating such things. There seems to be a lot of scale and not much erosion as I would expect an anode to have. I want to make sure it’s doing its job. If it’s not, why, and what steps do I take to remedy it?

 

[Cutwater28GG]

looks to me that the entire anode has gone?

 

[Brian B]

The Yanmar zincs are short and stubby. Here’s a pic of a new one http://www.boatzincs.com/yan120650-13420-ZINC.html
Although yours seems to be intact I would squeeze it between your fingers and it may disintegrate. There are two zincs on the Yanmar. The lower one wears out faster as it is always in water. I check mine every few months and replace as needed.

 

[CaspersCruiser]

Although yours seems to be intact I would squeeze it between your fingers and it may disintegrate.

That is exactly what just happened. I was attempting to scrape away the scale and the surface underneath just collapsed like it was the scale holding it together. So it appears this anode (the lower one) was doing its job!

 

[knotflying]

You will find that the lower zinc deteriorates much faster than the top one. I think that is because even when shut down and even out of the water it is still laying in water at the bottom of the heat exchanger.

 

[captstu]

When I replaced the anodes on my 4BY2 The portion that screws into the engine was filled with the threaded part of the old anode. I bought 2 Replacement anodes and two replacement washers +2 replacement assemblies.

I cleaned the scale in the engine by removing the top anode and filling the block with barnacle buster that I purchased from Amazon. When I took the old anodes out, the caps looked brand new and the remaining zinc from the old anodes was gone.

I installed the New anode assemblies as planned and kept the old parts to install next time.

The engine is now running 10° or so cooler and Anode protection is back like new.


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796