🔍 Key Concepts

• Exhaust back pressure and how it affects gas flow out of the cylinders • Impact of poor scavenging on combustion quality and engine cleanliness • Relationship between exhaust flow, temperature, and carbon buildup in engine parts

💭 Think About

• If exhaust gases cannot escape easily, what happens to the fresh air charge entering the cylinder? • How would restricted exhaust flow affect the burning of fuel and the cleanliness of nozzles and passages? • Which of these options would logically get worse, not better, when the engine has to push harder to clear exhaust gases?

✅ Before You Answer

• Confirm which of the choices represents a negative consequence of restricted exhaust flow • Eliminate any options that would normally improve with better breathing and lower exhaust restriction • Think about which component is most likely to be affected by incomplete combustion and dirty exhaust conditions