Thank you for choosing Just Answer, my name is XXXXX XXXXX I will do my best to help you find the answer you need to resolve your problem.
Are you sure the choke is sticking? I would remove the air filter and check the choke visually to make sure that it is open all the way. If the linkage is working correctly then you can add a few drops of penetrating oil to the shaft that the choke rides on to free it up. If the choke is not sticking and the engine just acts like it is then you will need to remove your carburetor (diagram all the linkages first) disassemble it, soak all the metallic parts overnight in a commercial carb cleaner and then reassemble everything using a new carb kit.