I was able to test run the engine from this old Graupner boat I have. I used some 15/22 aircraft fuel in it with a 7x4 Scimitar aircraft prop and a gravity fed cooling water tank. I went with a heavier load prop as its what I had on-hand. The engine runs rather good and thankfully the nickel plating isn't peeling in the cylinder yet.
http://youtu.be/bKsKRhR59VA