Oh the horror, what happened to my 340...

Check and see if the carb has all its bits and nothing fell off and down the intake, and that the needle n seats arent pissing.
Check plugs for damage

That's what I am thinkin. Something's hung up in the carburetor makin it run rough and makin it shak some stuff around makin extra noise it normally doesn't. I bet when he gets the carburetor ironed out, it's ok again. Stuff just don't "tear up" for no reason. But the carburetor can kinds screw up at a moments notice sometimes.