Ripped a load of joists down today with not the ideal blade, 40 tooth. I could have forced the cut a few times. On the last cut it seemed to be labouring and poss slowed down. Just checked the bushes and they seem ok with plenty of length. Looked at motor vents earlier on and there were a few blue flashes nothing major. Could it just be overheating or could it need a new motor or is it armature? Will try it again tomorrow.