I have a saw just like yours. I burned up the puny 1 hp that came on it doing a bunch of ripping and replaced it with a 2 hp from Harbor Freight. If you do this, get only the compressor duty motor which is designed for constant use. 2hp can be used on a 120v circuit with no strain. When Harbor freight has them on sale, the 2 hps are near $70.00 - about half what you'd pay most anywhere else for a brand new motor. Yes, they are Chinese made if that bothers you.

I forgot to add: there is a Sears parts source at: http://www3.sears.com/