A hit-and-miss engine, also known as a Hit N Miss engine, is a type of stationary internal combustion engine that is controlled by a governor to only fire at a set speed. They were first conceived in the late 19th century and produced by various companies from the 1890s through approximately the 1940s. The name comes from the speed control on these engines: they fire ("hit") only when operating at or below a set speed, and cycle without firing ("miss") when they exceed their set speed. Here are some key features of a hit-and-miss engine:

• Governor: The engine is controlled by a governor that cuts off the ignition system when it runs too fast, which is the "miss" part. When the engine slows down, it allows it to "hit" again.

• Flywheel: A hit-and-miss engine is a type of flywheel engine. A flywheel engine is an engine that has a large flywheel or set of flywheels connected to the crankshaft. The flywheels maintain engine speed during engine cycles that do not produce driving mechanical forces. The flywheels store energy on the combustion stroke and supply the stored energy to the mechanical load on the other three strokes of the piston.

• Usage: Hit-and-miss engines produced power outputs from 1 through approximately 100 horsepower (0.75 - 75 kW).

Hit-and-miss engines were used for powering a variety of machines such as water pumps and generators. They were the first type of engine to be mass-produced for the commercial market. Today, hit-and-miss engines are prized by collectors who lovingly restore them to perfect running order to show them at historical fairs and festivals. They are also still used in some areas of the world today, although they have largely been replaced by more modern engines.