my brother got a new to him but gently used stihl chainsaw. as you can imagine, he wanted to start it up and use it right away, like a kid at Christmas. so he has a basically dead mulberry stump out back by the shed and commences to cut down inside of it. he cuts for a very short time, maybe 30 seconds, and the chain starts smoking. and seemingly dull he goes ahead and takes a file to it, then tries again in the same cut and instantly starts smoking again. now he is mad and goes into town to get a new chain, thinking the chain was just bad. as you can imagine, he tries again, with the same result. he just can not cut through this dead mulberry stump to save his life, he tried so hard he ended up turning the bar blue with heat, obviously ruining the brand new chain and possibly the bar, then called me for advice..... so lets hear your ideas on what could be the cause of this, what do you suppose was the culprit??? its kinda funny, when he figured it out a week later I laughed pretty good.