I watched the Scott Manley video about it. He was the one that speculated that it was possible. I don't remember if someone did the actual voice audio or if it was the NTSB test audio they figured out it could be done on.
Just make sure the oil is always topped off with whatever you want to use. You will not have an oil related failure for as long as you care to use the mower doing that.
Teflon is bad for engines so that turned it into just another thick oil additive. I use it to coat prover balls when doing water draws so they slide better.
Two of my sons and I watched it. It is cool and kinda boring at the same time since everything is automated. Wish they had some more views from the actual rocket.
Most small engines are aluminum bore. Some have liners. Would be more beneficial to just make sure both valves are closed if it sets for a while.
Throwing it under marginal cover and changing the oil every now and then will make it last longer than you care to use it so anything more is overkill.