I have been flying single engine GAs a bit lately - what is the basic proceedure for leaning the mixture. For instance, the FSD Commander comes with settings for take-off and cruise, but the manual did not discuss the fuel mixure?What am I looking for in leaning the mixure - what engine readings etc.Thanks!Colin

Leaning the mixture refers to controlling how much fuel is allowed into the carburetor. The fuel + air mixes there, allowing the engine to run, but as you climb to higher altitudes, the air becomes less dense. Thus, you need to "lean" out the amount of fuel going into the engine to compensate for the reduced air going in and to achieve maximum performance. As you climb higher (in the C-172, I usually start around 3,000 MSL), start working the knob out slowly... you should see an increase in engine rpms as you pull it out. Be careful, because if you pull it out too far, the engine will quit! :-eekMake sure you have the mixture turned on in the realism settings in FS. Also, as a side note, in the Cessna 172 in real life, while taxiing, it is common procedure to lean the mixture out somewhat to keep the sparkplugs from becoming fouled. FS doesn't model this, but if you want it as real as it gets, try doing that before you taxi out from the parking area, and push it back in to full before doing an engine runup.

It will vary from aircraft to aircraft but typically you want to set the mixture to rich to engine start, takeoff and climb up to 3,000 feet. Above 3,000 feet you want to lean to obtain maximum RPM

Around here (KSLC) which is 4200+ feet to start with, we lean right after starting the engine ( approx. 1/4 on the knob), and then rich of where the engine responds to reduced fuel flow like you mentioned. The difference, is that we don't go back to full rich for the landing in case we have a go-around. The amount of power between full rich (less takeoff power) & partially leaned is quite noticeable at these higher altitudes.L.Adamson

As everyone else has stated, it is a general rule of thumb to lean above 3000ft. That is how I was taught. As for correct setting it depends on the aircraft. Cessna's usually reccomend 50

Thanks all.