The paper presents comparison of a selected combustion parameters of dual fuel, spark ignited engine run on gasoline and methyl alcohol. To the testing was used a four cylinder Fiat 1100 MPI engine with multipoint injection of gasoline and alcohol to area of inlet valve. Preliminary tests of the engine pointed at significant differences of its performance when the engine was run on alcohol only and on gasoline only [1]. In connection with it an indicator tests were performed in order to determine, on their base, a differences present in runs of combustions of the both fuels. The paper presents comparison of maximal pressure, rate of pressure rise, average temperature of working medium, heat release rate, total angle of combustion and indicated efficiency. These parameters were analyzed both in function of crankshaft rotation angle as well as engine load. Obtained results show at different course of methanol combustion comparing to gasoline. Run of methanol combustion is more rapid, what leads to growth of engine efficiency and increase of maximal cylinder pressures. Growth of working medium temperatures during combustion, what can lead to growth of thermal load of the engine, can be included to disadvantageous phenomena. Performed tests point at necessity of engine tuning modification during feeding with methanol, what would enable to take full benefits of advantageous properties of that fuel. Simultaneously, optimization tests have enabled to restrict disadvantageous effects of combustion of methanol.