Turn the needles 1 turn counterclockwise after being completely (gently) bottomed out finger tight as a start to see if it fixes it. One turn out from finger tight was the stock Tecumseh settings for most motors, double check these settings in the service manual posted in the sticky thread just to double check. It's okay if the engine will only gives a few pops or sputters with the choke on, if you turn the choke off and it runs just fine that's pretty normal if you ask me, and sign of a well tuned motor. A engine should dislike choke. Also remember to hold the throttle open when starting it (especially when choked), that is normal starting procedure. If you haven't cleaned the carb yet, this may be a sign that you need to.