Carburetor Priming and Burn Injuries

Accidents involving gasoline are a major cause of thermal burns in the US.  Thousands of people visit hospital emergency rooms each year for treatment of gasoline-related burns. These accidents are often associated with careless use (misuse) of gasoline. Most accidents occur in the summer months, due to an increased use of gasoline for farming, yard work, and recreational purposes (e.g., boating). A lack of understanding of the explosive nature of gasoline by the general public contributes to both its improper storage and to its misuse as a solvent, engine primer, or fire starter. Gasoline burns decrease markedly in winter months, except for burns associated with carburetor priming to start cars.

Carburetor Burns

A relatively common cause of burn injuries involves pouring gas into a carburetor in an attempt to start a car. When a vehicle runs out of fuel, an airlock can develop in the fuel line between a newly filled gas tank and the carburetor. To provide an adequate fuel/air mixture, gas may be placed directly into the carburetor to prime the engine. 

Priming carburetors is a dangerous and
unnecessary practice and can produce explosion or fire!

Explosions may occur by 3 mechanisms:

  • Contact of the gasoline or its vapors with hot metal (i.e., the car’s engine)
  • Ignition caused by an electrical spark from the electrical system of the automobile
  • Ignition due to excessive gasoline in the intake manifold, causing backfire

Backfires and explosions can cause burns.   The occurrence of these injuries is often underestimated since many are small flash burns. Typically, the burns occur to the face, neck and arms. This type of injury is most common in young adult males.