After building a prototype from bar stock, Eldon Dwyer of New Mexico made the patterns and castings to produce a second engine that he used in his power boat in 1982. It was modified for an electric starter since it was not readily accessible once mounted in the boat.
In the early 1980s, Dwyer started a company called Robotronics that produced and sold a casting kit and drawings for the engine. It is not known how many kits he manufactured and sold. In the early 1990s, Paul Knapp’s Miniature Engineering Museum acquired his patterns, prototype, and this engine. The engine is 14”-long, 8”-wide, and 7”-high.