RE: Diesel .50s (mostly)
I found the SuperTigre .45 ABC with DDD head. I bought it about 3 years ago, today it provided an interesting story. When I first tried to start it it would not draw fuel. I opened the HS needle to about 4 turns, still no go. I opened the throttle about half way, it would fire a couple of times but still no go. I bottomed out the compression screw, it fired some more but would not start. Finally I opened the throttle to full and it started but could only manage about 4,500 rpm. As soon as I would try to reduce the compression or lean it even a little it would quit. I began to think I had bought a worn out engine but it didn't feel like it when flipping. Upon inspection the reason was obvious, it had been assembled with the sleeve rotated 45 degrees toward the front. The notch in the cylinder phlange was lined up with the exhaust side front head bolt. After proper assembly it started instantly.
Using the same 12x7 Graupner, DDD ABC mix and Hobby-Lobby spinner as the others it turned 9,800 rpm. It surprised me by being stronger than the ST .51, although the .51 has a lot of time on it, about 16 years worth.