The Coffman device used a large
blank cartridge containing
Cordite that, when fired, pushed a piston forward. A screw thread driven by the piston engaged with the engine, turning it over.[url=http://en.wikipedia.org/wiki/Coffman_engine_starter#cite_note-2][2][/url] This was in contrast with other type of cartridge starter which acted directly to drive the engine piston down and so turn the rest of the engine over, such as those used on the
Field-Marshall agricultural diesel tractor.