Originally Posted by rmdhawaii
Corse-R: In picture 1473 I noticed there is an APS "stamp" and what looks like some scratches on the the counterweight. Any thoughts on that?
Saw them when I dismantled the engine for a revision and cleaning (and of course, a photo session...

). Examined them with a 10x loupe and are scratches of the machining (look at them and you'll that are circular - done them with a rotating bit). Are inofensive, just the looks.