How do you lean the mixture for best economy cruise?

To achieve the best economy cruise by leaning the mixture, the correct approach involves adjusting the mixture control to decrease RPM to a level that optimizes fuel efficiency without sacrificing engine performance.

When the mixture is leaned, it means you're adjusting the ratio of fuel to air entering the engine. At best economy, the mixture should be lean enough to burn fuel efficiently while still providing sufficient power for cruise flight. This is crucial because a richer mixture uses more fuel without significantly benefiting engine performance at cruise power settings.

The ideal setting is typically achieved just below or at the point where the engine runs smoothly without stumbling or losing power, aligning with the goal of maximizing the distance traveled per unit of fuel consumed. By strategically reducing the RPM to a "best economy" setting—often termed “best power” or "cruise" mixtures—the pilot ensures that the engine operates efficiently, resulting in a more economical use of fuel during flight.

This method stands in contrast to maintaining maximum RPM or leaving the mixture alone, both of which might lead to excess fuel consumption without enhancing performance during cruise.