MDS 61 ABC Engine w/ Muffler, Slightly Used The engine has very strong compression and the carb is smooth. The MDS line of engines are made in Russia and manufactured for high compression. The engine runs on 0% (FAI) but really thrives on 10% nitro fuel. This engine is a lot stronger than the average 60 size engine but the carb is not the best and the ripmax display team always used to use and O.S carb to make them run well