A broken bolt could hurt it. You may have an air leak at the base of the carb. Did you take the carb apart when you cleaned it. You may want to rebuild the carb completely. I had a 2b holley on a furd and took it all apart, cleaned it and put it back together. Ran like crap before but ran nice afterwards. I didn't have a choke of any kind of it and it would still start when it was 10 degrees out-no joke! I would change the broken bolt and see if that makes a difference.