RE: Test stands for break in (not good)
Chainsaws & heat
I would think a Chainsaw engine would have a larger Piston to Liner "gap" than our plane engine,, I have seen 15yo saws that were so well taken care of yet had so much time on them that when we took them apart their rings have worn threw their Chrome Flashing in spots, and they still ran great,,
I stick to braking-in on the stand, brake-in a gasser plane engine on the stand is fine as long as you are "smarter than the engine"
Jim