My MS460 has a winter and summer setting on the inside of the air filter / spark plug cover. The idea of the change is to draw pre-warmed air from around the motor housing in the winter, and to draw fresh cooler air from the outside environment during the summer months. I would say that if you were running your saw on the winter setting during the summer months, this definitely wouldn't aid in the cooling process. Change it over and see if the problem is rectified!