Edelbrock 650 Thunder Series Carb... Issues! HELP!

I have tightened up the spring to the point I thought it was just way beyond the typical adjustment. The result was less of a stumble / hesitation but it was still there. Squirter size would be stock I am not certain what it is though. I did also try moving the accelerator pump to the highest setting. It did not change anything.

Something else I should mention is that we had a new edelbrock performer 600 sitting around and we threw that on to see and it worked fine.

Thanks for the response.