Well if you are looking for a manual of the tractor which of course includes details about the engine you can find it as downloads here: Operator's manuals (specifications are in part 4)
But I guess you already have that, would be strange to buy a 3 year old tractor which has lost its manuals already.
In general, what do you think of the tractor?
I've driven that model (A92) a little bit. I don't like it. Or more exactly I think is to outdated in the design. But that what is expected of a value tractor. In fact the platform is a relic, from the 70ies which has been upgraded along the way many times. Mostly I miss a power shift gear, which a lot of competitors in that range has. Heck, my MF 175 from the 60ies have that (multi power).
Otherwise I love Valtra as a brand, I would very much like to own a N Direct -series.