What term describes a fuel/air mixture that contains too much fuel?

A fuel/air mixture that contains too much fuel is referred to as "Too Rich." In the context of combustion engines, a rich mixture implies that there is an excess of fuel compared to the amount of air available for combustion. This can lead to incomplete combustion, resulting in higher emissions, reduced fuel efficiency, and potential engine performance issues. Understanding the balance of air and fuel is crucial for optimizing engine performance and emissions standards.

The other terms do not accurately describe a mixture with an excess of fuel. A balanced mixture refers to the ideal ratio of fuel to air, while optimal generally pertains to the best operational conditions for performance. Excessive might imply an overarching concern but does not specifically capture the precise nature of a fuel/air mixture that is too rich.