🔍 Key Concepts

• Backfire flame arrestor purpose – what problem it is designed to prevent on gasoline engines • Where air-fuel mixture enters the engine vs where fuel is stored or sparks are created • USCG small vessel safety equipment requirements for gasoline inboard engines

💭 Think About

• On a gasoline inboard engine, which component is directly exposed to air and fuel vapors where a backfire could ignite them? • Which choice represents the part of the engine where air and fuel mix and enter the cylinders, rather than where fuel is just stored or where ignition occurs? • If an engine backfires (flame travels backward out of the intake), which component needs protection to stop that flame from getting into the boat’s interior spaces or bilge?:

✅ Before You Answer

• Make sure the option you choose is the part that handles the air-fuel intake into the engine, not just ignition or storage. • Eliminate components that only store fuel or only deliver spark, since those are not where a backfire flame would exit into the open air. • Recall that USCG requires backfire flame arrestors on gasoline engines with enclosed compartments, mounted on the engine’s air intake/mixing component.