The discoloration on the exhaust cover could be from the plug wires.
I found a Mark 7 that was really nice. Original paint but not as pristine
as Johnrude’s motor. Coils indicated it hadn’t been run in years. Tag
may indicate it was last run in 1959. When I took these plugs out they
had never been fired. They are J7J’s. Hard to find a crossover chart
that even list them today.
Tubs.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.