Hello All,

I am hoping someone may be able to help me....
About 4 weeks ago I changed the anodes on the various coolers of my Yanmar engines. When I was looking around the engines yesterday I noticed a bit of corrosion/furring on four of the nearby brass plugs on the various coolers. The anodes I fitted when not specific Yanmar anodes but generic pencil zinc anodes. I removed one of the plugs to have a closer look, its was very weak and snapped off when trying to refit. The brass had also changed to a pinkish color.

My understanding is that the brass plugs are less noble and therefore have suffered galvanic corrosion.... can anyone comment on this...???? What I am now thinking is to replace the brass plugs with stainless steel plugs... but my concern is that I donīt want the coolers to corrode!!! i obviously want the anodes to waste not the coolers. Could the anodes be the wrong material? I have heard of some engines using different types of anodes.. maybe magnesium..?

This boat is new to me and is the first time i have changed the anodes. When I removed the old anodes they were completely wasted and there was no corrosion/furring on the brass plugs. Not sure of the history of the anodes being changed

Any information would be greatly appreciated.

Many thanks in advance.....