I have an echo srm260 string trimmer that has been acting up since i bought it used. It will not idle without feathering the trigger and I have to run it at about half choke to get full power. There are no pins on the carb that I can tell to adjust except for the screw that adjusts the throttle cable. I have played with that and no luck. Today I took everything apart and cleaned everything really well. Took apart all of the carb and cleaned it, cleaned the exhaust manifold/port, took the piston out and cleaned the dome and rings etc, still same results, it runs fine when in the half choke position but still will not idle. Does anyone have any suggestions. Sorry for the long post. Thanks in advance to anyone who can help me with the problem.