Was cutting down a big wht. Oak couple days ago was working the saw I guess too hard and all the sudden was pulling the saw out letting off the throttle and it hi reved. Tried to hit the kill switch keep on. W.f.o. had to choke to kill it. After it stopped I could hear what sounded like fuel bubbling like it was hot. Let it sit for couple minutes started it up ran fine and kill switch was working?? Any body know anything bout this. Not really happy with the saw. Run good fuel mix. Don't use it often. Bought it new. Thanks