I just found in the manual a picture of the OMP that shows it using a washer to adjust clearance. Can't post a picture yet, it's in Adobe, having a hard time figuring out how to get an image copied. (I guess I could print it then scan it, but scanner is still in the box)

Basically, I would think adjusting one direction makes more oil flow, the other, less.

I'd probably remove it though, because if it's leaking, it's still going to leak.

(NOTE: This is all conjecture on my part, as I can't seem to FIND it even yet. If I need to, I'm sure I will)