I have several saws and my standby number 3 backup saw is a Stihl 028 that I have had for several months. I was given this saw by my son's father in law because it was dead and had not run in at least 12 years. Anyway, after some repair it turned out to be a good running saw with lots of compression. The problem I'm having is the chain gets tight when it gets hot and it'll lock up and stall the saw. I have to start with a loose sloppy chain and it still gets as tight as a banjo string. I would have thought a hot chain would get loose, like my other saws. The chain oiler is working fine and that is not the problem. I guess I could try a new Stihl chain and see how that works. My other good Stihl saws don't do that. So what is happening? David.