I have HRX217HXA model and after doing regular maintenance like changing oil, spark plug and air filter, started same thing as yours. As soon as throttle lever moves to slow, it stops the engine. I was thinking of changing the carb but after reading one post here, I will just clean it since that did not solve problem.
There may be a cut off switch that the throttle lever at the carb hits to kill the engine.
If the cable slips under the clamp it can activate the kill switch too soon.
