ryobi cs26 weed eater won't stay running

I have a ryobi cs26 weed eater that won't stay running. I haven't ran it in probably 8 months or so, and I should have known better. First thing I did was dispose of the old gas and also pulled apart the carb to see if anything was gunked up and it was fairly clean except for the little mesh filter screen, so I cleaned that out and put it back together. If I choke the engine and give a couple of pulls, the engine attempts to start and once I switch to full throttle, it will run for about 3-5 seconds and dies. In order to get it to run for another 3-5 seconds, I have to choke it again and once again give it a few pulls. Then the cycle continues. Never able to get it to run for more than 5 seconds, and I did this for probably 45 minutes.