posted 12-11-2006 10:47 AM ET (US)
JimH, thanks for posting the Duke of oil article in the reference section. It was very informative. In a search for more recent information, I came across this article concerning the Mercury synthetic blend oil.http://www.mercurymarine.com/uploads/images/1949/LubricantsArticle.pdf
While it does not disclose the content of the oil, it does point out the importance of the new FC-W certification. For what it is worth, I've been using this oil in the Yamaha F 150 (Outrage 18) since its first oil change and have been happy with it. It is a little on the pricey side but with one oil change per year, I think it is worth it.
Also, here is a link to the NMMA FCW oil certification site where the list of certified oils and the testing procedures can be viewed.
http://www.nmma.org/certification/programs/oils/fc-w.asp
Like all good research, this information answers some questions, while posing many others. I hope it will be useful to those that are interested.
Ron