have a Sear Craftsman riding lawnmower model 502.251220, with a Tecumseh 10 hp engine, model # 143.426072. DOM 5074R. The side cylinder wall is crack and want to repower the mower. Is there anyone that can tell me if there is a cross refenced motor to install in this mower? I picked up the lawnmower cheap and don't want to invest alot into it.