ORIGINAL: ArcticCatRider
If the glowplug, piston dome, piston skirt.....are all relatively smooth looking and not discolored or "burned" looking.....it should be OK.
If you don't feel and roughness in the crank, and it turns over velvet-smooth, and has good compression....it should be OK.
If it runs well at all stages....it should be OK.
I've owned several engines that have had their "signature" sound. Take the baffle out of the muffler, and run it....then tell us what it sounds like and if the cackling goes away. Otherwise, I'd enjoy that great engine.
The top of the piston looks good. It turns over good and has plenty of compression. It's doesn't hardly cackle when I am running it on the bench before flying, only cackles in the air! I took the baffle out about after my first 5 flights when it was new and I got more power out of the engine by doing that.
I just checked my low end needle and the book calls for it to be opened 2 1/2 turns for openers. It was out 2 3/4 of a turn. When I have an os engine I usually have to turn the low end "in" if anything. Maybe it was out to far at 2 3/4 turn out as it was at the field today. I wonder since the low end is so rich at 2 3/4 out if that would be causing it?