Loud Rattle on 22hp Kohler, Craftsman Lt2500

[dborshe]

Kohler 22hp on Craftsman LT2500 - loud rattle, unable to determine where it is coming from in the motor. Isn’t deck or pulley related, took deck off, no tension on drive belt. Gets louder with higher RPM, but doesn’t seem to change in frequency or pitch.
Any ideas?

Here is the sound recording- https://drive.google.com/file/d/1tukzLlcwTsAui4KkJYFKPshHsKbAuEOs/view?usp=drivesdk

 

[DaveTN]

Doesn't sound like a rod knocking or broken camshaft, so that's good. Sounds
more like a rattling than a banging. Hate to tear it down just to find it. But it could
lead to more serious damage if not fixed. Still trying to visualize what it is. Reminds
me of a loose muffler vibrating against the block or frame. I have at first mis-diagnosed
a loose engine mounting bolt for a rod knocking. Sound from one cause can mimic
the same sound coming from another cause entirely.