Well, back to this again since I have a little time. The knocking noise to me seems related to the engine. It is a 3-cyl. gas. When I first start it up, there is no knock, then I add more accelerator and a tiny knock starts. Then after working for a while the knock is louder. But, if I put it in idle, it does not knock. What do you all think this is? Any other information, just ask, and I'll try to answer.