Like Tom NJ posted, the OEMs had to put something in place to protect themselves (from boat owners from using convienance store 10w30??).Thanks guys, I read that paper’s abstract and will check out those links later. The abstract talked about high ZDDP being good to protect boat engines, but bad on car catalytic converters. Like I mentioned earlier, Yamaha still says it is acceptable to use API oils in the engine. If API is OK, wouldn’t a diesel be better with its higher HTHS and more anti-corrosion additives and detergents? If I read old threads correctly, CAFE and LSPI concerns caused auto oils to change and be less suitable for boat engines, which drove the marine guys to do the FC-W label. But I still haven’t heard a reason other than “trust the manufacturer” for why a strong diesel is a bad choice for a marine application, or what the differences between a marine and diesel oil are.
Most automotive 10w30s are slightly lacking in the HTHS department. Most boat owners would not know the difference between a PCMO and HDEO. Not to mention the new FA fuel economy 10w30 HDEO.
The Vanderbilt web site lists several antioxidents for engine oil.
For some reason www.aftonchemical.com didn't light up on my last post.