Join Date: Dec 2010
Location: Slidell, LA. USA
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3 GM 30 Yanmar, White Powder
We have a 3 GM 30 Yanmar in our boat. The engine looks and runs like new, but is about 10 or so years old and has been properly maintained since new.
The other day I climbed into the lazarette to check the Racor, which is behind the engine. At the rear of the engine is a 2" X 2" flat plate held on with 4 12MM bolts which also secure the engine lifting eye, and a small clamp securing a hose. On the top and bottom of the plate where the edge touches the engine, there is a white powder substance which looks like shaving foam emerging from the crack between the two surfaces. It is dry and I cannot find any trace of water leaking from the area.
This is the second time it has appeared in a month. The first time I washed the area down with distilled water and assumed that something had spilled there.
I suspect it could be corrosion as I have had experience with a similar appearing substance on aircraft. I cannot be certain but do not believe that there should be any salt water contact at that location. I am wondering if the heat exchanger has been compromised, allowing salt water into the fresh water side. Yanmar uses no anodes in this particular engine. I detect no salt contamination in the cooling water, which appears normal in color. I have no idea what is behind the plate and need to determine that before removing it.
Any ideas or suggestions?
William Atkin Cutter, "TALLY HO MAJOR" "ROSA"