Gas Engine Magazine

The Hercules Engine News

By Staff

20601 Old State Road, Haubstadt, Indiana 47639

In one issue of the Sears and Roebuck catalog it states that the
first Thermoil engines were produced at the Hercules factory at
Evansville, Indiana, in October of 1915. The first Thermoils were
listed only in the 1917 catalog and were available in the 2, 5 and
7 HP sizes. So far about 40 of these model T Thermoils are known.
These models were prone to breakage problems because their
construction was too light. They were built on modified gas engine
castings. By 1917 the production of the model T Thermoil had been
discontinued until a heavier Hvid type engine could be

The instruction book and list of parts adds another dimension to
these early Thermoils. In the parts list there is a column and a
listing for parts for the 1 HP size. Further on there is a table
showing the dimensions for constructing a masonry base to mount
them on for permanent installation. In addition to the 1 HP
information, there is also a dimension listing for the 9 HP

Up until recently, there has been no clue as to the existence of
the 1 or 9 HP model T sizes. But that has changed now. A 1 HP model
T Thermoil has surfaced. It is number 249. It is shown in the two
pictures here. It is somewhat more modified in construction than
the larger sizes. It has a two piece base, somewhat similar to the
regular two piece base used on a few of the 1 HP Hercules engines.
The flywheels appear to be identical to those used on the 1 HP
Hercules and Economy engines of that time.

The engine pictured here appears to be complete except for the
fuel line to the injector. It is unknown as to whether it has been
run recently or not. The color is green. These early Thermoils were
originally a sort of light lime green, with the typical Thermoil
decal only with a red background.

During the August 2000 Tri-State Gas Engine and Tractor Show at
Portland, Indiana, the new owner, Tom Buchanan of Indiana,
Pennsylvania, picked up the engine. As was mentioned earlier, a 9
HP size is also listed. There have been rumors of such an engine
existing, but so far no verification. It should be pointed out that
this article refers to model T Thermoils and not the later models U
or UA.

  • Published on Jan 1, 2001
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