Ditching a quick fuel carb.

I had a similar issues with a 625 Demon and it ended up not being the carb. I had weak spark from a bad coil and poor ground to the ignition box. You could also have a vacuum leak under the intake. Was the block decked? Are you running a vacuum advance distributor and if so is it plugged into the spark timing vacuum port? The choke be it manual or electric needs hooked up. If manual wire it open if electric make sure it is wired and working.