So awhile ago, I posted that my dad bent the crankshaft on his lawn mower by hitting a cement block. He was going to continue to use it until it finally broke as it was knocking like mad! Well a few days ago, he was cutting some tall grass which put some load on the mower and it stopped knocking! I heard it before and it sounded like two metal rods smacking each other and now, it sounds completely normal. What in the world is happening? Has anyone ever heard of this? Oh, a new engine is on the way just in case.