Here are some photos of the upper bearing surface on the crankshaft and the damaged cast aluminum bearing surface in the lid. As I think I previously mentioned I have not disconnected the blade clutch and transmission pulley or removed the engine in order to remove the crankshaft from the crankcase. I think I am correct in thinking that the upper bearing depends on oil being pumped up to the top of the engine for lubrication, while the lower bearing is immersed in oil due to the oil laying on top of it in the bottom of the crankcase