I have a Honda self-propelled lawn mower. At the end of last use, the self-propel stopped and it smelled like burned rubber. I checked the oil, which is fine, checked the blades, no blockage or build-up on inside of mower, and the belt looks fine (I thought the belt might be hung up on something or broken, but it looks O.K.) I can turn the blades manually with no problem. The spark plug is new. The cord is extremely difficult to pull and I can't get it all the way out. Also, when looking under the mower, what is the best way to tip the mower? Lift the front, or turn it on its side?