Wish I never found SN!
I had a look at a 2001 Yanmar that was in a boat here Oz, what was unusual was the paint around the sump, lower block and the plate attached to the front of the engine was coming off in sheets. The exposed metal appeared to be aluminium and where the paint had been it was covered in a fine white powder. My first thought was that it was corrosion caused by electrolysis? Or that the motor had not been properly prepped before painting. Other than that the motor was extremely clean with no signs of oil leaks or rust. Could this paint problem have been caused by cleaning, degreasing with a cleaner such as chlorine.