This is the old-style design of the St. Marys engine, which pertains to the valve placement on the engine. It has a vertical governor, hot tube ignition, and an unusual cast iron exhaust port pipe.
This particular engine pumped oil at several locations in Duhring, Pennsylvania, for the Duhring Development Co., which was owned by Chesebrough Manufacturing Co. — manufacturers of Vaseline. None of the oil from the Duhring field was ever used in the making of Vaseline, but it stood by as a backup. An actual oil sample from the well that this engine ran can be seen on the shelf.
A geared, walking-beam unit belt driven by this engine pumped one well, while at the same time, a rod-line connected to this geared unit pumped a second well some distance away utilizing an Oklahoma-style rod-line jack. Dr. Paul Harvey purchased the engine from Bill Summers and brought it to the Coolspring Power Museum in 1968.