Yanmar SB12 Burning Oil!

[a64pilot]

Now change the oil.
99% of the wear material happens in a very short time and you what that out of your motor.
Then go run her hard, don’t baby it, that is the worst thing you can do to a new Diesel, you want to run it hard, reason is to raise the cylinder pressures, high pressure forces the rings against the cylinders and ensures they seat well, the first few hours on an engine will determine if it burns oil or not for the rest of its life.
If you look at a new ring you will see the inside is at an angle, that angle causes gasses to blow the ring out against the cylinder, that is why a ring has a top and a bottom and you don’t put one on upside down.

Most rings anyway, I assume there may be a few that are not made that way, but either way run her under a load to seat the rings