My echo weedwacker seems to have a fuel or air problem. The primer button will not always inflate and seems to have air in it. Weedwacker will run but start to bog down after a little while then won't run for any period.

I replaced the fuel lines, fiilter, air filter, spark plug, new primer button, and new gas.

I would actually take carb apart and clean it out and check the gaskets/fuel pump. A tiny bit of dirt in the carb can wreck havoc here. There tweaked so close in tolerances

YouTube - how to fix 2 stroke weedeaters (http://www.youtube.com/watch?v=y1xsHICIBqk&feature=related)