In the paper are discussed test results of dual fuel spark ignition engine with multipoint injection of alcohol and gasoline in area of inlet valve. Engine fuelling was accomplished through a prototype fuel supply system comprising duplex injectors controlled electronically. Implemented system enables fuelling of the engine with pure gasoline, with pure methanol, or simultaneous combustion of the both fuels mixture with any fraction of the alcohol. The tests were performed on four cylinder, spark ignition engine of Fiat 1100 MPI type. In the paper are presented criteria to be fulfilled in dual fuel spark ignition engine run on gasoline and methyl alcohol. The criteria were developed on the base of engine testing performed on engine dynamometer. When developing the criteria, one took assumption of energetic equity of fuel doses in traditional and dual fuel supply system in every operational point of the engine. The second criterion consisted in maintaining a minimal elementary dose of gasoline and alcohol injectors, which would assure stable operation of the engine. In result of the performed analysis one proposed a map of possible ranges of dual fuel feeding of the engine with methyl alcohol and gasoline.