I started my equipment 2 weeks ago, evrything ran fine. I go to start my trimmer yesterday, and it keeps bogging down. It runs decent if I keep one hand on the gas, the other moving the choke back and forth. It will start right up after stalling, just can't get it to run normal for 10 seconds. while running w/ no choke, it runs nice then starts to bog, so i go to the choke, then it runs nice for a few seconds, then back to no choke....? Its not the muffler because I removed the little screen that collects carbon 2 years ago. I still took the muffler off anyway and gave it a scrape, but it runs the same. I tried w/ filter and without the filter, same. Would bad gas do this? the gas isn't that old, i got it like the end of january. Like i state all the time, if i bring it in to my local shop, I'll get it back in 2 weeks!!!!! Any ideas, its gotta be something minor and stupid. Thanks. Oh, by the way, its an echo srm 2100 weed whacker (trimmer ) 3 years old.