With the sustained interest in Unmanned Aircraft Systems UAS and Micro Air Vehicles MAV the military services have a real need for vehicles powered by an internal combustion IC engine that can run efficiently on heavy hydrocarbon fuels especially JP8 due to established logistics. This thesis concerns the results of running a two horsepower 4stroke sparkignition engine FUJI BF34EI with both isoOctane and nHeptane. Results include the knocking characteristic of this engine with nHeptane a comparison of the brake specific fuel consumption BSFC of the two fuels in a factory delivered engine configuration over a 17x10 APC propeller loading a comparison of the heated fuel effects on BSFC and torque of the two fuels and the effects of varied spark timing with nHeptane on BSFC and torque.