The focus of this research was to see how the air-fuel ratio alters engine performance and emissions while the engine was running on ethanol-gasoline compositions. This study was conducted using a single cylinder four stroke spark ignition engine, a dynamometer, and an emission analyzer. The air-fuel ratio was manually controlled, and then several percentages of ethanol-gasoline blends were utilised in the engine. Torque, braking specific fuel consumption, carbon dioxide (CO2), carbon monoxide (CO), and unburned hydrocarbons (HC) performance and emission tests were done at various air-fuel ratios and engine speeds. Leaning the air fuel ratio reduced CO2 and HC emissions in the same way that pure gasoline did, but unlike pure gasoline, ethanol blends had superior combustion characteristics at lean operating limits and greater engine speeds. Leaning the air-fuel ratio and utilising ethanol-gasoline blends resulted in considerable reductions in CO and HC emissions. The study also explained how to build an analytical model for the given statistical problem. The application of ANOVA to enhance the performance characteristics of a 4-stroke spark ignition engine was investigated in this article.The facilities established for performing experimental work on the test engine experiment were described in this paper. The SI engine was subjected to theoretical, experimental, and statistical evaluations, as well as the prediction of performance characteristics using ANOVA.