wongaga said..
I had read in this forum of the known problem of rusting and failure of the little lube oil line that runs from beneath the starter around to the rear of the cylinder head, but hadn't looked closely at mine.
That pipe sounds like it is feeding lube oil to the overhead rocker gear, which while critical, it is not near as critical as the similar pipe on my Yanmar 2 QM 15.
The pipe is between the filter and the main oil gallery feeding the crank shaft. If it was to let go I think it would dump all the oil in a few seconds.
The pipe is copper but the banjos are steel and will rust. I can't remember if I was able to find brass banjos or not but I did remake the whole thing with new parts and have cleaned up the old one to keep as a spare.