Hi I have a lawn-boy self propelled lawn mower with a Tecumseh 6hp engine. It leaks oil at the top of the engine under the flywheel. I removed the old top shaft seal and replaced it with a new one and I am still getting oil leakage from the same place. Could it be that the shaft has worn too much around the seal lip area and the new seal isn't getting a good seal there? Or could it be leaking oil around the crankcase ventilation seal? thanks