Great Western engines as offerd by Rock Island Plow Company for 1911 were available in several styles and sizes. Among them was the vertical tank cooled style. Among them were the vertical tank cooled style shown here. Using a two cycle design, these tank cooled engines could be purchased in 5 and 6 horsepower sizes, with the company guaranteeing that each engine would develop its rated horsepower. A water circulating pump was standard equipment – in a rather unusual design, these engines featured low tension make – and – break ignition instead of the spark plug ignition so often found on two cycle engines. THe 5 horsepower engine shown here weighed 950 pounds – the entire package was mounted on massive oak skids over 7 feet long.