Could be a few different things. I know you said you have compression but make sure your head bolts are tight, make sure nothing is restricting the muffler, make sure your intake manifold is tight, make sure the slide in the carburetor is going up and down when you spin the throttle. if you're running the NT make sure the choke isnt being left on and idle is up enough to make the engine run. Make sure you have good gas. If all else fails I had a Magneto issue where it would run until it warmed up and then it would stall but that doesn't seem like your issue. What carburetor are you using?. You can also try disconnecting your kill switch if you're using one. I don't use my Killswitch but for emergencies. After I slow down I just let the clutch out slowley if I want to stop the motor