Stumble at initial full throttle

It deisels cuz the throttle is too far open. The throttles are too far open cuz the AFR is too rich. The AFR is too rich,cuz fuel is getting into the intake that is either bypassing the low-speed circuit, or the float level is just too high.
To check for a too-high float level,just pinch the rubber fuel line ( or shut off the electric pump), and wait. And wait. And wait.
One of three things is gonna happen as the fuel level goes down.
A) the engine will speed up, then hang there, and then slow down and soon stall
B) the engine will hang there , and then slow down and soon stall
C) the engine will slow down and soon, stall.
In A) the starting level is too high
in B) the level is just right
In C) the starting level is too low
This is only true if the intake is not seeing fuel from any other source besides the low-speed circuit.
Is your accelerator pump check ball or check valve in there for sure? For sure?