When an engine starts running rough due to carb icing, this rough running is partly due to :
a) the airflow in the carb being restricted
b) the engine running too rich
For those 2 reasons, it is good practice to :
c) Apply full carb heat
d) Lean mixture to peak EGT initially, and enrichen again as soon as the engine picks up power when the ice is melting off.
Because of "a" the airflow being restricted, the engine is not pulling full power, so you can not hurt the engine by "d" leaning to peak EGT.
But you have to enrichen again, as soon as the engine starts running normally again.
My personal procedure is :
a) detect carb ice
b) pull FULL carb heat
c) advance throttle to full power
d) lean to peak EGT
e) wait for the engine to pick up power again
f) enrichen mixture again
g) push carb heat in when engine is running normally
h) set power to cruise
i) lean back to cruise mixture
Normal downwind procedure from cruise power:
- Pull carb heat
- Reduce throttle
Speed, gear, speed, flaps, speed turn, and so on.
- On short final, about 200ft, PUSH carb heat IN, check stabilised, if OK land, if not OK Go -AROUND.
- Hands on stick/yoke and throttle till standstill, or till stable climb-out, positive VVI, ready to retract gear, flaps for another go.
THE trick to a good landing or Go-AROUND is : Only ONE item to think about.=> Throttle forward in case off.
That is why the short final check is so important.
At about 200ft on short final, you and the airplane have to be configured and stabilised for a landing, or a Go-Round.
The only difference between them being a SINGLE THROTTLE increase without having to think about anything else.
Below 200 ft ?
One hand glued on stick/yoke.
Second hand glued on Throttle.
And don't you dare touch anything else till standstill, or a positive and confirmed climb out.