Cummins ISL G 300

The register lists here five versions from ISL G 250 to ISL G 320 – the number in the model name gives the output in horsepower – with 250 to 320 hp rated output at 2,100 to 2,200 rpm. Mixture formation runs through throttle body injection for natural gas as fuel, and the engines were certified for model years 2012 to 2016. Maximum torque ranges from 660 to 1,000 Nm at 1,300 rpm.

The ISL G chiefly drives transit buses, school buses and refuse trucks in municipal and regional service, where operators favour lower emissions and running on natural gas rather than diesel; it is one of the best-selling natural gas engines in this power class in North America.

Unlike the diesel engines in this register, the ISL G is a spark-ignited engine with spark plugs rather than injectors as the wear item; on a used purchase, what matters is the condition of spark plugs and ignition coils, the tightness of the natural gas fuel system including the pressure regulator, the inspection date of the gas tanks, and operating hours and service history of the catalyst system. Spares and service run through the Cummins dealer network.