The paper presents findings from numerical simulation on utilization of syngas in 3 cylinder diesel engine, 8.75 kW power, used in a small gen-set, based on the. concept of syngas-diesel dual fuel. It is the first step of the process of applying syngas produced by biomass gasification system to the diesel gen-set to be used in rural areas. The simulation model was created on AVL Boost software, of which Vibe 2 zone combustion model was used for the prediction of combustion characteristics, Woschni 1978 was selected for heat transfer model, while NOx, CO and soot emission calculation was based on models developed by Pattas & Hafner, Onorati and Schubiger, respectively. With the constant rates ofthe syngas containing of 11.63 percent H2, 24.47 percent CO, 0.01 percent CH4, 0.08 percent O2, 1.79 percent CO2 and 62.02 percent N2, the simulation results show that at the engine speed of 1500 rpm and indicated mean effective pressure, IMEP = 6.54 bar (at the full load condition), the syngas could replace upto 60 percent of diesel fuel consumption. The specific energy consumption increased and exhaust emissions including CO and NOx were raised while soot emission decreased with the syngas quantity of the dual fuel cases.