This shows to be an older model. Can you provide a couple of pictures? That may help us help you. As near as I can tell, this is a Briggs and Stratton engine. If that is the case, there will be numbers stamped on the engine valve cover.
Sears did not manufacture their mowers, they were private labeled by others who actually build them.
#3
sgkent
a Google shows this for that model. Click on the photo to see it better.
