The engine I was working on is a Kohler Command CV22S. It is a 2001 and running great. I had just changed the oil and was test running the engine. During the checking of the oil level I noticed that it was a little foamy. That should have set off an alert. I continued noting that the oil level was correct and assuming it was ready to run. Test ran the mower and it work as expected. Later on in the week I got an email from the volunteer that mows the grass and uses the above lawn mower. He stated the mower was running fine and then he heard a "clunk" and the engine stopped. I inspected the engine and found that it had broken both connecting rods. I took the engine apart and found that a "welch" plug had come out of the oil pump and thus the oil pump was sucking air causing a lose of oil pressure, thus causing the catastrophic destruction of the engine. Why Kohler would use a "welch" plug in the oil pump is beyond me. It did last 23 years, but would still be going strong if it would have stayed in place. Kohler will never get my business again.