On a small passenger vessel backfire flame arrestors are installed on?

• A. Gasoline powered engines
• B. Diesel engines
• C. Steam engines
• D. Electric motors

Answer: (A)

Backfire flame arrestors are placed on the air intake of gasoline engines to stop a flame front from traveling back into the carburetor or intake manifold. Gasoline engines can produce a backfire that, if it reaches vapors in the engine space, could ignite and cause a fire. Diesel engines don’t rely on a carbureted air-fuel mixture and backfires into the intake are far less of a concern, so they don’t typically require these devices. Steam engines and electric motors don’t operate with the same kind of intake flame risk, so flame arrestors aren’t needed there. That’s why they’re installed on gasoline-powered engines.