You really shouldn't need a choke in August lol. Try pressing the primer on the carb bowl a few times for good measure and it should fire up just fine without it. As for fixing it, take the enrichment valve out of the carb, if it isn't stuck in there. You'll figure out pretty quick if its the valve or the cable. The valve assembly is about $35, and the cable is around $8. If it were mine I'd just order both anyway and keep any good old parts for spares.