No, the blockage makes it run richer masking hesitation problems.
For hesitation problems it is almost always the poorly assembled recharge check valve in the accelerator pump.
At the very bottom of the accelerator pump assembly there is a small brass insert with a ball bearing above it. As the pump is moving down on the pump stroke gas flowing up around the ball sucks it up against it's seat causing the gas to be forced out the discharge path in the bottom of the carb.
The problem is that the replacement pumps do not have the brass insert pressed in far enough. This leaves too much clearance between the ball above it and the ball seat. With too much clearance the gas flowing by can not lift the ball up against it's seat. (I know, funky design)
If you hold the pump upright and look between the four slots between the ears that hold the insert in, you will see the ball.
I see them with as much as 1/16" clearance between the ball and seat. I put the pump in my vice and press the insert in so there is about .015" clearance.
This is the most common problem but not the only one you could have. In some cases the leather hangs up in the bore stopping it from moving and pumping.
Sometimes the link between the pump and throttle arm is mis-adjusted.
