oil out valve cover vent on TB 007 with Yanmar 2TN66L-UTBA engine

so its been parked for the better part of the winter. just got started to move out of the garage in anticipation of some digging. about 45 seconds or a minute after start notice oil dripping off one track and turns out it was coming out of what I would call the road draft tube on an automotive engine, i.e. the crankcase ventilation which is just a tube from the top the valve cover running down the side of the machine that ends right above the track.

the guy who moved it freaked out and thought he must have lost lots of oil and put a quart in which only lead to more of the same obviously . (and he didn't know where the dipstick was, its kind of obscure on this engine.

so he shut it down and called me. we drained the oil back down to the operating range and everything seems hunky dory. but I'm trying to figure out what might have caused the first incident of oil discharge.

pulled the valve cover and didn't really see any drain holes as such so couldn't estimate if they might be sludged up or . . .

wondering if anyone has had any experience with this engine. seems they use 'em in refrigeration sometimes I've been told, although the net seems to suggest they are limited to sailboats and TB-007 in the sense that I can't find any other uses or applications when googling for that model engine.

Thanks for any knowledge of this little power plant.

brian