Chainsaw Repair

Yes, one could melt the piston on a brand new saw just by adjusting the carb incorrectly.  You can sit it on a bench, and slowly turn the high screw in and get it really screaming, say 16,000 to 18,000 rpms for 40 or so seconds.

You need to "richen" the mixture to slow them back down to 13,000 or so, depending on the model.

Also, since the lube is in the fuel, the leaner the mix, the less lube there is for the engine, which makes it overheat
exponentially.  So if one is using his saw, and it starts acting squirrelly and dying, he needs to shut it off and fix the problem.