Thanks Max, I appreciate the explanation and the details
I had an interesting conversation with my uncle who was the former owner of the Pope engine. Now get this! He says he only ever ran it on 25ml of 2-stroke oil to the litre, and he first bought the mower in 1964. When the mower finally fell apart, he kept the engine and converted it to horizontal and used it to to run an air compressor right up until the 1990s. In all that time he only ever gave it 25ml to the litre. He said he ran that in all of his 2 strokes always and never had any problems. I told him what the manual said and he couldn't understand why anyone would want to add that much oil, even in those days. He said "You'd look like an old steam train coming along if you were to use 40ml per litre or more." All I can add is if he was going to kill the engine by using 25ml per litre, it sure has taken its time to die. :-)
