I had this problem 3 weeks ago.
The positive wire to the electric choke was bad and it was flooding. I had to constistantly feather the petal and most times off the line i had to let it idle up to speed before applying any gas (funny sight to see!).
Anyhow, changed the wire, choke works now just fine. Just have to retune the carb to get rid of a surge at crusing speed.