The Model G was in production from 1918 to 1924 and a total of 7,949 Model Gs were produced by Rumely.
The G weighed 11,000 pounds and featured a two cylinder engine with an 8 inch bore and 10 inch stroke. The engine operated at 450 RPM. As with other Rumely designs the cooling system employed oil and the exhaust was ducted into the top of the cooling radiator. As the exhaust gases escaped upwards, cool air was drawn along with the gas and in doing so was drawn through the radiator so cooling the oil.