Check the init ref page and see what the Eng rating is in the FMC. This is the rating of the engine, do not exceed this power setting by turning off the autothrottle. Take care of the engines and they will take care of you, use as much reduced power as possible. We currently have a 737-300 that has 22K permanently derated to 20K, due to high temps at full power for 22K. This will save the company a lot of money by not having to overhaul.
Hope this make sense to you, please do not over temp by setting power with autothrottle off
