One other question on a related note:
Where is the idle adjustment screw on these engines? I see the two nuts under the gas tank but this seems hard to reach/adjust.
On mine the idle speed screw is on the top of the carb right at the end of the cable. The idle mixture screw is hard to see. It is at the very rear of the carb kind of tucked down from the top a little. 1-1/2 turns out from closed is about right for me but I am at 6,700 feet, so maybe 2 turns out might be right at sea level? A slight bit on the rich side should help to keep it from stalling at very low speed. If you haven't adjusted the mixture before I suggest you start at 1-1/2 turns out then slowly turn to the left until it starts to roughen up a little then turn back to the right just enough to smooth out the roughness, make the adjustments slowly.