Engine not running good

The timing hasn't moved since I set it last. I wondered if I set the gear in wrong from the start. (when I rebuilt the engine last year)
I cleaned and blew out all the passages in the carb and the mixture screw adjustments do effect idle quality. I can darn near kill the motor by turning either screw in to it's seat and it will run rough when I back it out to the rich side.
I haven't checked for timing chain slop but I installed a new Cloyes double roller when I rebuilt it a year and 2000 miles ago.

Mike