I got the head off and found that the exhaust valve seat had moved leaving the valve not fully seated. I reset it and put it all back together. Still no start. It sounds like it has better compression but I can spin the crank by hand (took the strator case off) so i dont know if it lacks compression still. Don't know if valves still have leakage, timing, or electrical (shut off) issue.

 

I just fought with the same problem for 2 days. Rebuilt the carb and all.. still wouldn't start. Had spark if I put it near the head. Anyway.. went and bought a new spark plug and she fired right up. Not to mention the spark was 10x as strong against the head as the old plug. Amazing stuff! lol Also for the carb screws, I had the same problem today, a pair of vice grips worked wonders on the screws. Once you pop them loose they will come right out