Weedeater want reb up put new carburator 230 echo weedeater

I know this is a very old post, but figured I'd answer it so any others with this issue can have the fix.

With Echo trimmers not revving to speed although they start with no problem, the issue is usually the muffler screen. It becomes plugged with carbon because of improperly mixed 2 stroke fuel.

Remove the screen from the muffler and burn off the carbon with a propane torch, or wire brush it off. Once cleaned engine should rev to speed.