Beginning in 1921, the Hercules Gas Engine Co.
introduced what I would call sort of an oddball engine. It featured
a one-piece block with a 3-5/8-inch bore. When introduced, it was
rated at 2 HP in the Hercules, Jaeger and Economy brands. From the
very beginning, the ARCO brand was rated at 2-1/2 HP. Photo 1 shows
an early one with a dry four-bolt head. Interestingly, it has a
larger-than-normal Webster magneto, which means it has the seldom
seen 303K32 bracket. Two other obvious features are the slanted
rocker arm and the side exhaust.
On some of the earlier engines, there is another unusual
feature. The spindle for the governor shaft is cast as an integral
part of the engine base (Photo 2). This means it takes a special
governor bracket rather than the more common one that this size
engine shares with the smaller engines. If you look closely in the
photo, you can see the spindle between the flywheel and the hopper.
Another oddity is the oiler pipe location. It seems to be just
stuck in behind the hopper (Photo 3).
The Jaeger engine shown in Photo 4 is a more typical example of
this size engine, with the four-bolt wet head and side exhaust,
slanted rocker arm, oiler through the hopper and Wico EK magneto.
The fuel spout position can be seen on the front of the base. There
is another a fuel tank spout at the rear of the base.
The last example shown is the seldom seen throttle-governed
kerosene version with the fuel mixer sticking out from under the
head (Photo 5).
Somewhere along the line the engine’s horsepower rating was
increased from 2 HP. Both the Hercules and Jaeger brands were
increased to 2-1/2 HP and the Economy brand was increased to 2-1/4
HP. Why was the Economy brand only re-rated to 2-1/4 HP instead of
2-1/2? I suspect it was done to avoid confusion with the earlier
2-1/2 HP Economy Model E engines.
Some people ask, “Are these engines rare?” The answer is no,
they really aren’t rare, but rather, just odd. However, within this
group, those with the dry head, spindle on the block, oiler behind
the hopper or kerosene mixer are rarer.
Glenn Karch is a noted authority on Hercules engines.
Contact him at: 20601 Old State Road, Haubstadt, IN 47639;