I don't know about the chain and bar flying off, like some of the others I've never even heard of a bar coming off a saw. As far as not running, check to see if it's flooding. If not flooding it needs an adequate spark, fuel, air, and compression to run.
Which of them does it not have? It could also be the spark arrestor plugged up and creating too much backpressure. Being a fairly new saw and the fact that it will run sometimes, I'm thinking a bad plug. They are all fairly easy to check.

Those who are always shooting off at the mouth usually aren't shooting straight.



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