20 hp Koehler Engine noise, abnormal?

I just had a 20 hp Kohler courage come in for service...with a clack clack clack sound......after running for a few minutes to determine where the noise was coming from, the heavy steel counterweight came through the block. Opening up the engine for the autopsy, I fount the aluminum arms holding the counterweight had shattered, after apparently a bolt or two had come loose........good luck.

Video on f-book no work. Nice pictures of a truck & people, mountains, and a dish antenna?
Why not post on youtube? You just need to set up an id, and you have a 'channel' right then.
If this machine uses a Kohler V-twin, they are pretty good engines, even when they have the 'Courage' label attached. The Courage singles had problems with the top cover bolts loosening, sneaking out of the threads enough to get whacked by the flywheel, causing the case to shatter. For one thing. As noted above, the balance shaft design may have a flaw also. Some who had religiously changed oil, still had a running engine come to pieces for no apparent reason, connecting rod in pieces. Scared me from even considering one.
That said, you have multiple things you can do. Check that the engine mounting bolts are still holding the engine tight to the chassis or mount. Check that the PTO, pulley or whatever, has its bolts tight. Check that the key or grub screws are still tight. A loose pulley can make a good lot of noise. A loose engine can seem to be coming apart, and quiet down a whole lot just by tightening a few bolts & nuts.
Check that all the 'tins' on the shrouding are tightly in place, that the intake or carburetor are still tight to the cylinder head. You might want to check under the shroud, especially for something that is exposed to a lot of 'chaff', as said chaff can aggregate and block cooling air, along with mice, wasps, insects and any other critter that wants protection from the elements, and can fit in. They'll nest, and block the air. If you have mice in the neighborhood(a joke. They are almost everywhere) and they have access, they can move in... and they don't pay the rent, etc.
If you consider it is a rod bearing that is coming loose, you can remove the engine, and take it apart enough for access. You can then check the rod journals on the crankshaft and the rod bearing surface of the connecting rods. Go from there.
tom

Just an opinion, from afar, that does not sound like a loose valve train. It sounds like a rod knock. Unless you have a shaft drive where power is taken from the flywheel end of the crankshaft, which could have loose/broken parts, the engine itself is likely the source of noise.
Looking at the images here:

https://www.jackssmallengines.com/j...ro-and-60-mower-deck/engine-group-20hp-kohler

It appears you may have a shaft drive. I would inspect all the drive parts, and make sure they are all tightened properly. You could have a failed/failing universal joint, or just some loose bolts. Access may not be fun. If possible, you could grab the drive shaft that goes from the engine rearward, and try to shake or move it around radially.
It should not move, and should be firmly attached at both ends. If loose, inspect more closely. That thing is likely worth putting new/used parts into it rather than going for a replacement.
tom

You can get an engine manual from kohler's web site. Service manuals in PDF format are cost free. You will need the model number etc to get the correct manual, which will likely cover many more models.
The Command/Magnum(?) singles were equipped with hydraulic lifters as note by the holic, but I think the V-twins used mechanical valve adjustments, at least on SOME.
There was a recent post that had similar noise, and the problem was in the PTO, where some stuff in the electric clutch was loose, or the 'pin' that holds the clutch steady was loose or similar. He had gotten something that flew up into that area... sounded as if the engine was eating its connecting rods, but the problem was the PTO. Lots easier and less costly to repair.
tom

Thanks.

Do you happen to remember the thread name or close to it?

I may have to try some of these suggestions, like it or not. I stopped at a engine repair place on the way home just 20 min ago "If it has an Engine, we can Repair it!" Is their motto. Well they said it would probably be cheaper just to buy a replacement new engine. Not a good start.

I can't believe as good as that engine runs and as freely as it spins that it needs thousands to repair.

Anyone know of any reasonable engine repair places near Louisville Ky.?

Read this one:

https://www.mytractorforum.com/14-craftsman-sears-forum/1324895-engine-knock-something-else.html

Sounded similar to yours, and it has an electric PTO clutch that turned out to be the noise source.
tom