I have a Weed Eater GT-15 gas string trimmer that won't stay running. It has worked fine for 15 years, but last time I trimmed with it I tried to finish my lawn and ended up running it out of gas. I refilled it with fresh gas, but it wouldn't start. Let it sit a day, and I can get it to run with quick-start, but it dies out when that is burned up. Fuel tank was spotless, and in tank filter was also spotless. Running out of ideas as to whats wrong. I know I have good spark and compression, so it is fuel delivery related, and running the tank dry has done something, but what I'm not sure...