Well, there is excellent info about a similar situation on this thread. https://aomci.org/forums/topic/1973-evinrude-mate-2hp-issues/. Compression problem was solved by replacing the block with one from a parts motor. I do have a parts motor but it also has low compression. I will take a careful look at the rings and see if there is a location pin in the piston, then make a base cylinder gasket, put it together and if there is no improvement assume that the bore is just worn out.
