My wife's co-worker asked me to look at a saw that wasn't running right. Just needed some fuel system work, but luckily I decided to strip it down a little farther and take a peek at the piston. It was a good thing I did, since I found this little hairline crack. If it was one of my own saws, I am sure I would have just fixed the fuel problem and went to cutting, only to have it grenade later.