Ringmaster wrote:
I have a Yanmar 2GM and I just buy a top quality 30W regular oil which
is what Yanmar recomends. I also use a Yanmar filter but have also
used FRAM.

I too have been using 30W. However its a real pain to change. I've
recently been talking to some motorcycle enthusiasts and they claim
that with the premium synthetic oils they need only change it every few
years - it just doesn't breakdown in the same way a normal oil does.
So the question is whether this is any this applicable to the yanmars?
A friend of mine speculated that with this type of diesel motor the oil
becomes contaminated more readily and thus would require changing
regardless.

Can anyone provide some insight?