This is a fairly early 1897 6 HP Mietz and Weiss. Designed by Carl Weiss in 1893, it’s a 2-stroke engine with a three-port design and it’s a semi-diesel.
A unique feature of this engine is the hot tube ignition. There is an uncooled cast iron bulb in the protective shroud at the head of the engine, which is heated to a dull red by an external torch in order to start the engine. When the engine is in operation, the injector sprays the fuel downward onto a lip extending into the cylinder from the cast iron bulb where some of the fuel will bounce and spray back into the bulb. The fuel then readily combusts and ignites the rest of the fuel in the cylinder providing the power for the stroke. Once the engine starts, there’s enough heat from the combustion process to keep the bulb hot without the pre-heater.
Made by August Mietz Co., NY
Serial no. 579
Ignition: Hot-bulb vaporizer
This engine is one of 40 being profiled in a new book about the Coolspring Power Museum being published by Gas Engine Magazine. It will be available for purchase at the upcoming Coolspring Summer Expo, June 16-18, 2011.