Choking the engine restrict the air intake into the carb, and in turn the amount of fuel being drawn through the carb into the cylinder. If it seems to only seems to want to run with the choke on, the you most likely have a fueling issue. As in its not able to draw enough fuel through the carb for the amount of air its getting.

Check the fueling system from the filter, to the carb and possibly the carb itself. Replace and fatigued diaphragms.