I just got this and found that it would stall out when i shut the choke off.  i looked into it and checked the carb which looked to be fine but i blew it out and put it back together.  the spark plug looked ok.  i adjusted the idol and it now seems better and not stalling out when the choke is off.  Now the issue is that it is backfiring quite often.  anyone got any ideas of what this could be or what i could do.  

by backfiring do you mean it is cutting out or that it is actually backfiring throught he exhaust??

reason being, if it is cutting out then it is normally a sign that the fuel/air mixture is too lean.
and turning the fuel/air mixture screw to the left 1/4-1/2 turn should help it out.

you turn it a little more if needed, but remember that if it starts bogging down then it is too rich.

check the diaphram in the top of the carb as well for holes or wear.  this could cause backfire to some degree.

and barring that you'll need to check the timing and the valves.