Thanks for the updates. I have not found any reference to any tech updates, and the on-line manual I downloaded was from Yanmar so I would have expected any corrections to be in that - it is not the same as the original manual (in several languages on each page) so they could have easily changed the spec if they wanted to. I have not found the traqnny ID plate yet - it has been painted over along with the prior owner's regular touch up painting of the engine with Yanmar grey paint - nice thick stuff that seems to fill in engraved info nicely
I tend to think that the engine oil is likely correct, since the prior mechanic used it in mine (I'm pretty sure from color) and lots of people on these forums seem to think it is right also. I want to change it just for routine maintenance over the lay-up, but I may wait a little longer to see if any more info surfaces.