20601 Old State Road, Haubstadt, Indiana 47639, Glenn.karch@GTE.net
A caller recently told me about what he considered to be a rare model Economy 1? HP model JK engine. I didn't have an answer to all his questions at hand. Luckily, some time ago my good friend Bill Dawkins of Royal Oak, Michigan, gave me quite a list of these engines that he had observed along with some casting dates and notes on other features.
The J series of Hercules-built engines was introduced in 1930. The earliest casting date seen so far is December 4, 1929, and the lowest serial number seen so far is 1007. The latest casting date seen is October 10, 1933 with the highest serial number being 10570. Production apparently was about 10,000 of these J model engines.
By far, most of the J models were the JK (kerosene and gasoline) and were marketed through the Sears mail order catalogs as the Economy brand. A gasoline JI (gasoline only) was sold along with the JK under the Hercules brand. In addition to the 1? HP size, there was also a 2? HP size, but they were not nearly as popular and only accounted for about 10% of the production.
Around serial number 7000, several minor changes in the engine design occurred on the 1? HP size. The round breather tube at the rear of the engine was changed to a rectangular shape. The flywheels were modified to use a clamping bolt rather than a set screw to hold them in place. The modified flywheel then had a keyhole shaped slot rather than the plain look of the earlier ones. A dip stick was also added to make checking the oil level easier. The street elbow at the rear could now be turned down as an oil drain.
Four of the accompanying photographs show the before and after of these changes and the fifth photo shows the proper location of the Economy decal on the top of the water hopper.