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.