Starting fluid

Diethyl ether, with a small amount of oil, a trace amount of a stabilizer and a hydrocarbon propellant, has historically been used to help start internal combustion engines because of its low 160 °C (320 °F) autoignition temperature. Some current products sold as starting fluid are mostly volatile hydrocarbons such as heptane, (the main component of natural gasoline) with only a small portion of diethyl ether, and carbon dioxide (as a propellant). It is often useful when starting direct injected diesel engines or lean burn spark engines running on alcohol fuel. Some formulations include butane or propane as both propellant and starting fuel.

Diethyl ether should not be confused with petroleum ether (a crude oil distillate consisting mostly of pentane and other alkanes) which has also been used for starting engines.

Charcoal is pre-soaked with ignition fluid to help ignite the coal.

Starting fluid is sprayed into the engine intake near the air filter, or into the carburetor bore or a spark plug hole of an engine to get added fuel to the combustion cylinder quickly. Using starting fluid to get the engine running faster avoids wear to starters and fatigue to one's arm with pull start engines, especially on rarely used machines. Other uses include cold weather starting, vehicles that run out of fuel and thus require extra time to restore fuel pressure, and sometimes with flooded engines. Mechanics sometimes use it to diagnose starting problems by determining whether the spark and ignition system of the vehicle is functioning; if the spark is adequate but the fuel delivery system is not, the engine will run until the starting fluid vapors are consumed. It is used more often with carbureted engines than with fuel injection systems. Caution is required when using starting fluid with diesel engines that have preheat systems in the intake or glow-plugs installed, as the starting fluid may pre-ignite, leading to engine damage.

...
Wikipedia