What are some common causes of rough running engines?

A rough running engine is often indicative of issues related to fuel delivery and ignition. Choosing vapor lock and fouled spark plugs as common causes provides insight into specific mechanical problems that directly impact engine performance.

Vapor lock occurs when fuel vaporizes in the fuel system, disrupting the normal flow of liquid fuel to the engine, which can cause erratic engine performance or stalling. It's particularly relevant in certain environmental conditions, like high temperatures, where the likelihood of fuel vaporizing increases.

Fouled spark plugs can also significantly affect engine efficiency. Spark plugs are responsible for igniting the air-fuel mixture in the combustion chamber. When they become dirty or coated with carbon deposits, they struggle to create a proper spark, leading to incomplete combustion. This results in rough running, misfires, or an unstable idle.

The other options touch on various aspects of aircraft operation, but they don't directly connect to the engine's running quality as clearly as vapor lock and fouled spark plugs do. Incorrect fuel type and propeller balance might result in other performance discrepancies, while low battery voltage and weak ignition can lead to starting problems rather than rough running during operation. Excessive weight and uneven loading are more related to performance metrics such as takeoff and landing rather than how