The combustion processes optimization is one of the most important factors to enhancing thermal efficiency and reducing exhaust emissions of combustion engines [1; 2]. Future emission regulations for small two-stroke SI engines require that the emissions of gases causing the greenhouse effect, such as carbon dioxide, to be reduced.One possible way to reduce exhaust gas emissions from two-stroke small off-road engines (SORE) is to use biogenic fuels. Because of their nearly closed carbon dioxide circuit, the emissions of carbon dioxide decrease compared to the use of fossil fuels. Also biogenic fuels have a significant influence on the combustion process and thus the emissions of different exhaust gas components may be reduced.Besides greenhouse gases, several other exhaust gas components need to be reduced because of their toxicity to the human health. For example, aromatic hydrocarbons cause dangerous health problems, and can be reduced by using alkylate fuel.This research shows the potential of gasoline or alkylate fuel blended with alcohol to reduce exhaust gas emissions. Blends of these fuels with ethanol, 1-butanol and 2-butanol were used. The exhaust gases were analyzed both with standard exhaust gas analyzers and with a Fourier Transform Infrared Spectroscope (FTIR). The combustion process was analyzed by interpreting the indicated incylinder pressure. Thus the influence of alcoholic blends causing combustion phenomena such as knocking was regarded.