Jeff,

I haven't specifically talked with him about synthetics, but there was a
post a while back from a guy who had used synthetic oil in his 5.7L Merc
and had some kind of premature failure. The subject was " Mercruiser Motor
Failures" from Feb 2003. You might want to search for it on Google and read
his post.

Also, if Mercury specifically doesn't recommend something I'd think it is likely
because they've seen some problems, and not because they just haven't tested
it.

YMMV,

Don W.



Messing In Boats wrote:

That's why I stuck out my timetable so far; I figure I will have this
and a lot of other things figured out by then and will know what I
should have done.

I am hoping for 2000 hours though. I change every 100 hours and run the
boat at hull speed, about 1800 rpm, which I believe to be a lot kinder
to it than up on plane at 36-3900 as it was designed for.

What does your buddy say about synthetics?

Jeff