The broken con-rod has a twist to it, this happens when someone finds a stuck engine (usually from long term storage or running without oil) and unscrews the cylinder without first attempting to free up the stuck piston, guaranteeing a snapped con-rod.
I've only had one engine so far with a snapped con-rod, it was in an almost unused looking Champ generator which I suspect the original owner didn't bother to add any oil to the fuel, I did manage to remove the stuck piston but never could get the rings off it.
As it used the later 14mm cylinder & oiling had failed to move it, the piston got pressed out (do-not try this with older 10mm cylinders).
I've also had another stuck engine with a holey piston, that too came out without any more damage (left oil in cylinder over a few days/week).
David