I mow with a 14 year old Craftsman. I've been through the carb once or twice. It stared running rough a few weeks ago. I was towards the bottom of the gas in my gas can so I thought it was that. New gas didn't help. The wife tried mowing last week and it died on her. I started it back up and it sounded like it was on its last legs...barely ran. I started removing plastic covers to access the carb. For some reason I tried starting it again with the air filter off. What do you know...it ran perfectly. Put the air filter back in place and it barely ran. I had a look at the plug and it needs replacing too. 14 years isn't bad for an air filter and a plug...