Well, this is my method how to lean the mixture:
- Established on the cruise altitude, set the cruise RPM
- Start to lean the mixture monitoring the EGT indicator
- The EGT starts to rise, follow leaning it slowly till it the engine reaches it’s peak EGT
- Once it reaches it’s peak (red line), the engine starts losing the power and runs a bit rough
- By enriching back the mixture only a little bit, the RPMs will increase again slightly and the engine will run smoothly
Advantage? You will get more power from your engine, more RPMs, you will fly faster and will burn less fuel and have more endurance. Thus the overall efficiency will increase :-).
You can see the same process in this 47 seconds short video in a Piper PA28.
Safe landings! 🙂