Including Economy, ARCO, Jaeger & Thermoil
20601 Old State Road, Haubstadt, Indiana 47639
During 1923 a new size Hercules built engine made its appearance. It was a larger one piece block engine with a 35/8 inch bore and 5 inch stroke. Initially it was rated at 2 HP but it was quickly rerated to 2 HP when sold as either the Jaeger or ARCO brand. In 1925 the Economy brand was rerated to 2 HP and the Hercules brand to 2 HP. Other than color and HP ratings, there was essentially no difference between the various brands. They shared several common parts with the smaller engines including the crankshaft, bearings, cam gear, governor, magneto bracket and a few other parts. Among the Hercules built engines it has several unique features. The valve rocker arm is set at a slant. The valves are side by side rather than up and down. The crankcase has no cast iron bottom. Instead the fuel tank creates the bottom. There are provisions for the fuel spout to be located through a hole in either the front or rear of the engine base rather than through the side.
Although they normally have a four bolt wet head, one dry head engine has been observed. One engine has been observed that has the governor bearing cast as a part of the main frame. All the rest have the bearing as part of the governor bracket.
This size of engine never became very popular. One of the factors affecting popularity was the fact that it was introduced after the gas engine heyday was over and sales of gas engines in general had begun to decline.
Of the 75 or so of this size engine known, the Jaeger and Hercules brands are the most common. They were produced in the FW, G, H, GH and S models, thus all were equipped with the WICO magneto system.
The accompanying photographs show this size engine.