Help! I need a crash course in leaning

[Slick Goodlin]

Yes, embarrassing to ask but it’s been a long time since I took a small airplane farther than the circuit and I don’t confidently remember how to lean an O-200. Looking for method by EGT and by RPM if you don’t mind.

Thanks.

[vanNostrum]

What works for me:
Lean until RPM increases a bit [ 25-30 RPM] continue leaning until
there is slight drop then go back to where the rpm peaked
Don't even have to look at the panel, your ears will tell you

[David MacRay]

I just do a variation of what van wrote. Having said that..

I lean for maximum airspeed in cruise.

He explained it’s basically just rich of peak plus it gets you to the destination faster. Makes pretty good sense.

Let me know if you want a link. He explains it a bit longer. There’s missing pictures, and “F” swears.

[Slick Goodlin]

Thanks guys, that tracks with what was in the recesses of my mind from my 172N days. IIRC it called for best power at 50RPM rich of peak and best endurance 50-ish lean of peak (RPM, not EGT).

I’ll be flying a 100 horse Cub with fairly minimal instrumentation so I’d like to get good gas mileage but also not kill it in the process. Thanks!

[Slick Goodlin]

Turns out it was a moot point, the mixture control was so coarse that I never did get it to show any rise and fall without just quitting. Instead I just pulled the mixture out to “arbitrary lean” which must have been pretty close since I ended up with the fuel burn I had calculated. I’ll call it a win.

You know what else is a win? Flying a J-3 seven hundred miles in a day. What a trip!

[David MacRay]

That does sound like a great time.