Sounds like you have some tiny crap rolling around somewhere in the carb. It plugs an orifice (very tiny in this sized carb) then falls away at some time allowing short runs or non-starts. If the carb is a Walbro type pull the side inlet and check the screen for debris. Pull the needles and blow or supply gentle vacuum through the seats. Reset the needles to default and try again.
If it starts and runs continuously leave the dang needles alone for a while until a little run time gets some clean gas through it. If the engine is new, twiddling the needles right away can add to or be the issue.
If none of this helps a complete fuel system review and/or a complete carb teardown may be needed or return it to the vendor and let them deal with it.
Good luck.