md: Check your fuel cap (vented) for restriction there should be a rubber red perhaps stopper within the inside of the cap which allows air to enter but seals to prevent gas spillage. You can verify quickly by opening the cap carefully when the unit begins it's symtoms.

Ok, I tried a couple times taking the cap on and off as it began to act up but it did not help. I also tried changing the "dial" to half-choke and that seemed to work one time but not again. So I am still nursing the trimmer along. It still starts very easily and runs for a while then shuts down. I can tell when it is about to shut down because the engine revs up and then shuts down. The running time is getting shorter though, maybe 15 minutes of good run time before it starts acting up. I'll take any other suggestions. Thanks, Mike

Have you checked or replaced the fuel lines with good tightly sealed lines at the carb and tank? Thinking it could be pulling air once it gets good and hot, below a fuel line tank entry (that should leak fuel possibly) or swelling line or seat to starve the trimmer. I experienced this timing matter with a swollen seat in a mower's carb. I guess they swell more as a water faucet's washer while running. A new seat solved the obvious problem that was noticed with the carb and float inverted and the float w/n level. I would think this is possible due to gasohol but how would you test this w/o a float w/o guessing?? loger

I would make sure the fuel filter (laying in the bottom of the tank) is laying at the lowest point. Fuel hose should have enough slack to let the fuel filter lay flat at the bottom of the tank at the user trimming level. I'm guessing the filter is coming out of the gas and sucking air. Just guess but you didn't mention how the filter was laying inside the gas tank???