Thanks guys:
i miscued re fuel, as i have used both over the years. I believe the muffler/engine seat is at fault, as it has only a very thin gasket, and "black stuff" seems prevalent at that joint. I'll remount and seal as recommended. Also re prop: IMO I am turning a bit fast, definitely not overlean (kinda known at the field as mr. rich, and it ain't because of $$), going to fit a 14x6 now that I have a little more time on the engine. ( A 14x6 is not in the mfg's recommended range, so I toned it down a bit during breakin).

Once again, thanks to all- -keep 'em flying.....