Another question. I bought a used OS .61 FS about 3 years ago. Just got around to starting it for the first time last weekend. I used Wildcat 15% nitro and 18% oil. It started up right off and ran great for about 2 minutes- just enough time to get the needle adjusted. Then it quit. At that point it had little compression. I took the engine apart to inspect the various components. The push rods looked good and functioned when I turned the engine- opening and closing the valves. THe head looked good also-no cracks or gasket leaks that I could see. The liner looked good as well-no scars or scrapes-the fit is still tight. The only thing I could not get out is the piston. This is a ringed engine and I was thinking that maybe I broke or compressed the ring-although if it broke it wasn't evident in the liner. How do you get the piston out of this engine? I tapped the liner out abot 2/3 of the way from the bottom-as far as I could reach. DO I continue to pull it out from the top to take enough pressure off of the piston to disconnect it from the crank? If this was a real car or truck engine I'd be more at home! Thanks, Tracy.