Do you have battery?
QT50 is using it to help you with starting (you have your "start" position on the handle bar).
Take off your muffler, many of the those little scoots have clogged exhaust and it will not start because of the back pressure, very common problem.
Is the spark plug oily whey you kick it?
If yes get rid of oil injector (mix you own fuel) because it is faulting your plug .
Pour some gas straight into spark plug hole, put new spark plug and try.
Follow Fred's guide in resources.