Coolspring Spotlight: 1910 35 hp Bessemer Twin

This 35 hp Bessemer twin engine at the Coolspring Power Museum was originally installed in a Pennsylvania courthouse to provide electricity.

| August/September 2018

1910 35 hp Bessemer Twin

Manufacturer: The Bessemer Gas Engine Company, Grove City, PA
Year: 1910
Serial Number: 10287
Horsepower: 35 hp
Bore: 8-1/2in
Stroke: 15in
Owner: Kevin Kusel

Bessemer made a wide range of oil field engines. This is an early commercial model which featured the enclosed crankcase. It is interesting that this is the smallest twin-cylinder model built, while the single-cylinder commercial was also built as a 35 hp model. The buyer had his choice! The Bessemer engines were very successful and the firm soon became one of the largest engine builders in the country.


This engine uses the patented Bessemer “star wheel” igniters operated by twin rocking shafts, as well as hot tubes. Both of these ignition systems were soon phased out in favor of the magneto and spark plug. Bessemer was an advocate of the 2-cycle design and indeed it proved very dependable. The frame was massive and yet provided easy access to parts for adjustment and repair. The engine is throttle governed by a vertical governor head with linkage to the gas valve. The wide, heavy flywheels indicated the engine was designed to power a dynamo for electric lighting.


The engine was originally installed in the Mercer County, Pennsylvania, courthouse to provide electricity for the building. When commercial power became available, it was moved to the J.F. McComb oil lease near Sandy Lake, Pennsylvania, where it drove a compressor. Paul Harvey found it in the early 1970s and brought it to the museum, where it remained on static display for many years. Acquired by Kevin Kusel, it now operates extremely well in all its original glory.