At last, I've had time to read through this thread.
The only 'old' engine I've ever had a up close and person relationship with is a Ailsa Craig 1hp (I think 🤔) that we had as an outboard motor on our tenders to get too and fro our boats when they were anchored off shore. It always reminded me of an electric whisk to look at, very small and compact but was ultra reliable, never left us stranded, thank goodness 🤣🤣🤣