Hello I am using the Asobo Cessna 172, most of the checklists I have found state that once the engine is started, we have verified the oil pressure and throttle at 1000 rpm, we should set the mixture to lean. When they say lean, do they mean the stick fully pushed out like cut-off or up to a specific amount? If I pull it fully out the engine will shut down again. At this stage the EGT is still at zero so I cannot do when I lean the plane in flight.
How does it really work in real life?
At airports within a few hundred feet of sea level, this isn’t necessary. As elevations rise, some leaning might be normal for taxi but it will be during the before-take-off runnup checks that any performance improvement will be measurable (RPM increase).
Thank You, to be clear, I can start the engine with mixture set to rich and then leave it like that until I am above the 3000ft and I start to lean if necessary? Would this be correct?
Yes, that is correct.
Leaning for takeoff would not be a consideration unless field elevation is a few thousand feet or more above sea level.
After startup a little leaning of the mixture (pull back the mixture until rpm starts to rise a little) is a good idea. This helps to prevent spark plug fouling. While below 3000 feet MSL a little leaning isn’t strictly necessary it’s a good idea. Above 3000 feet MSL in places such as Calgary or Denver and especially on hot humid days leaning the mixture is very important to provide full power to the engine. Remember to enriches the mixture for your run ups and takeoff or you won’t have the correct performance.
Power + Attitude = Performance
Additionally in 172s which have Carburetor heat, that should be turned on as well but then off while taxiing. (The C172SP Asobo model has fuel injection so carb heat is not an option).
When on the ground, and prior to taxi you want to have the RPM at 1000 and lean it right up to the point before it starts to run rough. If you don’t you will foul up the spark plugs.
No, if you taxi with full rich, over time you will foul up the spark plugs with lead deposits.
What @NotableFool6 suggests is correct for a carbureted C172, per the POH for the C172P model that I fly. (Recognizing that the one in the game is fuel injected, so procedures may be different for it.)