How can I fix Partner 351 chainsaw starting problem?

I have had chainsaw about 5 years. With choke on and fully primed it will occasionally start and then stop. Closing choke and repriming if I can instantly on firing open throttle fully it may start at full throttle and keep running. Once stopped difficult to restart. Could it be that some fuel has solidified/gone to jelly and is bloking fuel supply. Checking the spark plug it does not show signs of flooding - ie it is dry. Is it a carburator strip down and clean or are jets / fuel lines possible to blow out without stripping down carb.