Your jet size might be too small.
On my carter YF for the 235 57-62 the correct jet size is 395.
Anything smaller will give hesitation when punching the gas pedal.
The model number would help telling you if the carb is right for the engine.
I learned that there are literally dozens of carter YF versions all matching certain engines/years.
If you look at the long list of rebuild kits, you get the idea.
Very important to get the right kit, to make the carb work perfectly with the matching engine.
Could be that your carb was rebuild with different pieces.
