My 5U passes oil as when I restored it, I didn't do anything with the cylinders/rings because they were "nice and oily shiny" but I did work the head over fully with new valves, guides, and seats. In retrospect, I should have pulled the pistons when I had the engine apart and cleaned up the rings and grooves. I'm sure some of them are stuck or not able to fully move. When I initially cleaned the head up, the exhaust ports were choked (like 50%) with hard, oily carbon. The machine had been previously owned by a landscaper so I can imagine that it spent hours idling. The plan this year (will it actually happen?) is to get it on a plow and get it to do some actual work and get the engine temperature up. My understanding from other folks' experiences is that this would clean it up in the moment but won't solve the problem. I'm in no hurry to fix the issue so instead I'll put a curve on the top of the exhaust pipe so the oily smoke doesn't land (as much) on me