cousin brought me a 455 rancher he said wouldnt run. I pull the cord and it felt like zero compression. I could hold the cord and drop the saw and it would fall to the floor. so I checked the decom and it was good so I pulled the muffler. Muffler had gas pouring out of it, Its a good thing the saw wouldnt crank or it would have blown the muffler clean off.. Anyways, the piston and cyl looks as slick as a babies butt. So I am thinking just put a new ring in, then got to thinking, ring doesnt look stuck on piston, even tho there is plenty of carbon on the piston skirt. Why would the saw pass so much unburned fuel thru the cyl into the muffler. I havent checked the saw any further, but cant help but wonder why a saw with a slick cyl and piston have the compression value of a saw missing its spark plug.