swapping the carb shouldnt effect it.  Unless during the swap you damaged the o-ring or dont have a good seal anymore around the carb neck and too much air is getting in....May check that o-ring if you didnt before you tightened the pinch bolt..and seal the necessary spots.

+1 to rich settings puttin the glow plug out.....when the glow starter is taken off the glowplug, if the mixture is too rich it floods the plug puttin it out.  try to find factory settings and start from there......if its still too rich to keep the glowplug lit w/o the ignitor...lean the lsn until it will stay running w/o the ignitor.