At present, In India B7 (blend of bio-diesel 7% by volume in diesel) is notified and permitted to used in diesel engines. An alternative fuel for diesel has become essential due to the depletion of fossil fuel reserves and strict emission standards. Yet, given the characteristics of diesel, there is no direct renewable alternative fuel that can completely replace diesel. Thus, replacing some of the diesel with ethanol could be one of the options. In this study, the impact of various diesel-ethanol blends, including ED5, ED10, ED15, and ED20, was examined on two multi-cylinder engines in operation of varying vintages. The two engines under consideration complied with CPCB-I and CPCB-II, which is an Indian legal requirement for stationary Genset engines. For both engines, a 5-mode steady state test cycle was considered. For each mode, the engine's performance characteristics, including power, torque, and BSFC, were tested and described. Also, the emission pollutants such as CO, HC, NOx, Smoke and PM was measured for each individual mode. Almost all of the pollutants were seen to have improved. The drastic reduction level in PM and smoke level in tune of almost 50% was found promising. This research presents a thorough analysis of each mode and response of two different vintage engines to the use of a diesel ethanol blend. This paper also discusses the methodical process used to select the best blend out of all the tested blends.