Has good compression still but you can hold it wide open and it’s only hitting about 75 percent of its max rpm. Last time I put fuel in it it was none ethanol, is that ok? And I did run it little rich on oil. 1.5 gallons to 5 ounces or 2 bottles. Would this mess with it that much. Bought the saw new this year. Thanks. Plug is black. Didn’t put a new one in yet. Wired brushed it. Hit little higher rpm but stops in wood with almost no pressure. I dumped the gas and put in non ethanol 50.1 and still won’t rev. It started while cutting these tiny apple branches