What can cause improper ignition timing?

Improper ignition timing refers to the timing of the spark that ignites the air-fuel mixture in the engine's combustion chamber. When the ignition spark occurs either too early or too late during the compression stroke, it can lead to several performance issues such as engine knocking, reduced power, and increased emissions.

In a small engine, the ideal moment for the spark to occur is just before the piston reaches the top of its compression stroke. If the spark occurs too early, it can cause pre-ignition, leading to knocking. Conversely, if the spark occurs too late, it can result in inefficient combustion, where the air-fuel mixture doesn't burn completely and can lead to a loss of power and increased emissions. Thus, timing the ignition spark accurately is critical for optimal engine performance.

Other factors, such as throttle position and fuel quality, do affect engine performance but do not directly lead to improper ignition timing in the same way that the timing of the spark does. Proper timing encompasses the engine's design and tuning, making the specific timing of the ignition spark crucial to effective engine operation.