Including Economy, Arco, Jaeger & Thermoil
20601 Old State Road, Haubstadt, Indiana 47639
The largest size gas engine first built by Hercules was the 10 HP model D in 1914. It had a 7 inch bore and 12 inch stroke and was governed at 300 RPM. The shipping weight was 2525 pounds. Ignition was by igniter and Elkhart magneto.
Later in 1914 the same design engine with the same specifications was related to 12 HP and called the model E. Also later in 1914, two mechanical experts from the University of Illinois came to the Hercules plant at Evansville, Indiana. They conducted prony brake horse power tests on all size engines being produced. In their tests, the 12 HP size engine actually produced 14-38 HP. This was 120% of rated HP. Ignition on all but the very early E models was by Webster magneto.
There were several versions of the 12 HP size available from time to time including the following:
Half base tank cooled gasoline hit and miss.
Half base hopper cooled gasoline hit and miss.
Half base hopper cooled kerosene hit and miss.
Full base hopper cooled gasoline hit and miss.
Full base hopper cooled kerosene hit and miss.
Full base hopper cooled LP and natural gas hit and miss.
Full base hopper cooled kerosene throttling governed.
All of the engines were available in both the Hercules and Economy brands, except for the throttling governed. It was available as the Hercules brand only.
Shown in the accompanying pictures is engine number 176586. It is an EK (kerosene) model made in 1919. It will be at the 80th Anniversary Hercules Show at Evansville in 1994.
By 1926 the 12 HP size engine was rerated to 14 HP. The bore and stroke remained the same. A slightly modified governor allowed for a simple twist of a screw, thus raising the RPM from 300 to 350.
Currently your writer knows of 26 engines of the 12 HP size. Although there are likely some out there, none of the 14 HP size have been observed or heard of so far.