After about 5-10 minutes of mowing, the engine starts to surge or hunt. I have removed carb, cleaned and replaced mounting gaskets. New fuel with ethanol fighter additive, new plug gapped at .035, new air & fuel filter. I honestly believe it has something to do with the choke or fuel shutoff solenoid since if I find just the right spot I can get it run okay. But this is just past full throttle into the choke region on the throttle lever mount. It does loose alittle rpm in that range but it wont surge. I just have to play with it to find it. How do i go about setting the throttle or is it in that stinking fuel shutoff solenoid? I wish i could disconnect it, but obviously the engine wont run. Its a great little mower and engine, but when this happens, it will almost slow down to idle.