My Echo edger will run at top speed once you get it there,but if you open the throttle quickly the engine will bog down ,cough, die and not idle. The carb is torn down and clean The metering diaphram is pliable and the needle valve works in shutting off the fuel supply. I have worked on many carbs. But this situation always baffles me . I know this is a common problem and is usually a loose head ,clogged carb .or gasket vacuum leak but to me this one needs a further suggestions. Thanking You P.Burt

Try the air to fuel mixture screws some have to some have one.
It should be stamped beside them
H & L .If I take a 2 cycle carb apart I always put a kit in it and check needle arm setting.
Good Luck.

Hi,
What brand and model carb. Current ones use a check valve in the main jet because of the EPA. Spraying carb cleaner will free it, but follow with something like WD40 immediately to flush it and prevent damage from some components of the carb cleaner.
Peace,
Clarke