I would make sure there are no air leaks on the carb mounting and that the pulse hole is clear and aligned. ( I had to make a spacer for the carb thus two gaskets.) Plug gap .025" and coil to rotor .010" (business card) between pick-ups and magnets and tighten. Still no go, then check the diaphrams inside carb and the screen filter under the cover with single center screw. Clean with cheap generic sray carb cleaner.

You did not mention if the engine was new or used when you acquired it?