How do you understand B737 Engine warm up recommendations?

[flyzhz]

Hi ,everyone ,I have beening thinking about this question for a long time,but i can not find a good answer.
FCOM says:
Engine warm up requirement:
• verify an increase in engine oil temperature before takeoff.
Engine warm up recommendations:
• run the engines for at least 2 minutes
• use a thrust setting normallyused for taxi operations.

My understanding is " we have to run the engines for at least 2 minutes.What power should we use? We use a thrust setting normallyused for taxi operations".

Another understanding is "we have to run the engines for at least 2 minutes,so we can not takeoff whtin 2 minutes after the engines start.When we taxi,we use a thrust setting normallyused for taxi operations".

[EW73]

Second is good!

No hassle, if in 'normal' operations, you can start the second engine and get lined up inside 2 minutes, you're do'in really well!

:D

[Lord Spandex Masher]

I believe Boeing state that anything less than 60% N1 is considered normal taxy thrust.

[de facto]

A tip: an engine is considered “Cold” when its internal temperature is equal to the outside air temperature.No matter what the OAT is, thermal stabilization is achieved four to six hours after the engine is shut down.
For a cold engine, while two minutes is the strict minimum before applying takeoff thrust, CFM considers that 10 to 15 minutes at or near idle is needed for a complete thermal stabilization, in order to reduce all gaps, and therefore peak EGT at takeoff.

[Tinwacker]

Where would you be to start both engines and take-off before that 2 minute min time limit??
By the time the taxi duration and holding is completed you will be close to those times of 10-15mins given previously, for best take-off egt margin.