engine start timing b737 ng

[DrMcCoy]

hello friends,
i was wondering which timing times important when we start engine?
why do we check time after start lever to idle? i know there must be egt rise in 10 seconds and and there is gotta be 2 min must be passed before start second start attempt of engine. is there any other reason?
thank you

[JeroenC]

The EEC will cut off the fuel valve after 15 seconds after start levers to idle if no EGT. At normal FF of 390 l/hrs this limits the fuel to about 2 liters, preventing a so-called "wet start". The 10 seconds SOP is thee to make you feel YOU are still in control ;)
The 2 minutes "motoring" after a failed (wet) start is to expell this fuel from the engine.

Are you a line pilot?

[BARKINGMAD]

A "normal" engine will be up and running with start switch disconnected usually within 25-30 secs from start lever to idle.

Just F Y I after many (lucky?) successful starts.

The easy way of detecting abnormality is to watch the digital values of N2 and EGT.

The N2 figure is usually 100-120 greater than the EGT figure, except on new "tight" engines, even when started with residual EGT from the preceding running.

Try watching these, it might help you detect the next abnormal start in the sim, rarely on the line!?

Hope this helps? :)