The total mass fractions of the combustion gases in the syngas are 35%, 41%, 54%, and 66% respectively when the oxidizing agent is air enriched with 0%, 10%, 30%, and 50% oxygen. The Honda GX160 engine produces power outputs of 2.74 kW, 3.02 kW, 3.45 kW, and 3.82 kW respectively when using these types of syngas. Compared to the power before modification, the power output of the engine using syngas decreases by 33%, 26%, 16%, and 7% respectively. When injecting syngas through a single nozzle, the fuel-rich mixture region concentrates at the top of the combustion chamber, which benefits the ignition process. When syngas is injected through two nozzles, the fuel-rich mixture region concentrates at the top of the piston, promoting complete combustion. It can be approximately observed that Pmax (maximum pressure), Tmax (maximum temperature), Wi (indicated work), and NOx emission increase linearly with the oxygen content enriching the air supplied to the gasifier.