FWIW: I recently sold my 1998 Snapper 33" riding mower (SR1433) with 14HP OHV Kolher engine (CV14). I always used Purolator filters and 5W-30 M1 oil while I owned it (bought it from original owner in 2008 who well maintained it). Changed the oil ever year and the filter ever other year. Oil was always as clean as when new, never used oil, never smoked and always started on the first pull (7 year old battery died and I never got a new one). Thing ran like a well-oiled tank. I always mulched with the Ninja blades (both grass, leaves and small sticks). I had to replace the front wheels (finally dry rotted) but never the drive belt or other major parts. Stored dry. Great mower for my 1/2 acre yard. The reason it lasted so long was I (and the previous owner) took good care of it.
On a slightly different front:
I bought new a 22" Lawn Boy 2-cycle push mower back in 1993. I still have it today and it runs great! It was made with the Aluminum body that never rusts/rots. Always stored dry, used fresh gas (100% Gas) with synthetic 2-cycle oil (that also had the gas stabilizer it it). Still has original spark plug and while I pulled the bottom cover to clean the exhaust ports it was totally clean. Starts on 2nd pull. I now only use the TruFuel 40:1 fuel since I only use this as a trim mower (now little used).
They don't make them like they used to!
The Point: Buy wisely and take care of your stuff. You'll feel better and spend less money - then have a story someday of "how if used to be made in America".