Lady Kenmore dryer heats but doesn't tumble

I have a Lady Kenmore dryer model 110.96094100 that heats up but doesn't tumble. It use to be if I gave it a Fonzi shot near the top of the dryer, it would start. Now, it will only run for so long before it stops tumbling again (anywhere from >1 minute to 25 minutes or so). I've popped open the top of it and the tension belt around the drum seems pretty tight. I've opened the bottom access panel and noticed a slight ozone smell. Could it be the motor? How complicated a fix is it?