lsn probably needs adjustments. if you find the factory needle adjustments it'll give you a good baseline and you can go from there. but if you're still having trouble, not to scare you, but dieing when its warmed up can sometimes be a sure sign of a worn out motor in need of a rebuild, but i would play with the needles some more, mabye an idle adjustment.

if it started really easily it may have been because it was running lean, but it also would depend on the ambient temp. two storkes run best before they blow up, cause they usually end up running lean.