My gut is telling me the woodruff key is sheared.... It failed under load and the description is that it shut off like a switch. If there was an air leak that substantial, you would have noticed it revving way higher before it died. The fact that you could start it right after it died is more than likely because the engine was hot, so any fuel that was in there didn't have to compress as crucially at the right time. Once it cooled a bit, it became hard to start. I highly doubt on a compression or air problem. And if it was a fuel mix problem, you would not have gotten that far into the first cut and the Piston would be seized... You would know that instantly. The only other thing that would cause the issue the way you described it is electrical (spark plug, plug boot, plug wire etc.) But you ruled that out by saying you still have spark. You already said it felt like good compression and the Piston isn't scored... Engine failure is out. You verified fuel and spark. The only thing remaining on a 2 stroke engine is timing. The only thing that keeps it in time is the woodruff key. The fact that it failed under load makes sense in my mind. I am highly curious about this and can't wait to hear the outcome. I wish you the best of luck!!!
