MDS's of which I have 6 or 7, run superb on 5% or Zero Nitro fuel. Mine will out idle any O.S. at the field and turn up with the best of them. I have a .40, .46, .58, .61, .78, 1.48 and a NIB 2.18, The MDS line was created by the unemployed Russian Soyuz Scientist and Metalurgist after becoming unemployed when the Soyuz fellback to earth. They are my favorites in 2-strokes, and usually start first flip. Run 5% Nitro, use an O.S. Type "F" Four Stroke plug, and don't screw with the needle settings. Get them set after break-in, and 1 to 2 clicks only for future adjustments should work...