Direct injection of syngas into the cylinder leads to an increase in volume efficiency, creating a stratified mixture in the combustion chamber, which improves engine performance compared to the case of syngas-air premixed mixture supplying. Compared with the diesel operating mode, the power of the syngas dual fuel engine is reduced by 41.53% and 30.17%, respectively, with the equivalence ratio = 0.6 and = 0.85 when supplying syngas-air premixed mixture. With direct injection mode, the dual fuel engine power can be adjusted by changing the injection start time. Compared with diesel engine, the power of syngas dual fuel engine decreased by 25%, 21%, 17% and 13%, respectively, with starting injection at 55TK, 65TK, 75TK and 85TK with injection pressure of 5 bar. In any case of syngas dual fuel engine, the NOx emission concentration is very low, about 100ppm. Start injection in the intake stroke with 5 bar injection pressure is appropriate for syngas dual fuel syngas engine converted from the Vikyno RV165 engine.