Have you disconnected the inlet fuel line at the carb, and observed the flow to a container while energizing the electric starter?
Initially keep throttle closed for max manifold vacuum to operate the pulse fuel pump.
The latest original-equipment carbs are pretty much sealed up per federal mandate . . carb bowl screw heads are tamper-resistant, low-speed mixture screw has a metal plug over it, and the idle-speed screw MAY have a non-adjustable cap over the head.