Check the fuel lines in the gas tank. Probably crumbling and deteriorating. Ethanol!

After you checked all the lines and sure the carb. passages are clean as suggested you may have the High or low carb. adjustment screws off some. usually when it stall the high jet maybe adjusted too lean and require 1/16 to 1/8 of turn counter clockwise to alow more fuel. Some carb. you can adjust and some you can't. IMO anytime you have to choke it to get it to run three things mostly the cause. dirty fuel system, Vacuum leak, or carb. out of adjustment. IMO the choke will choke off the air and richen up the mixture alowing the engine to run faster but not at WOT speed Due to it being choked and starved for fuel at WOT.

I'm not sure if your model has a priming bulb, but it may be cracked.