External power or batt?
If External Power, is the Bus Tie set to ON, or just set to AUTO when starting the #2?
If you have it set to ON, then I'd have to have a bit more of a think about it, if set to AUTO, then try starting #2 with it set to ON and get back to us.
If you're starting on battery then Bus Tie will have to be set in ON position, to get the #2 bus to light up fully, but with external power it could be left in AUTO, but then it could possibly load shed a bit during the start if the voltage starts to drop?
Leaving it set to ON with an external start should force it to keep everything on line and will mean that none of the systems will drop offline during start if your external power fails.
What sort of external power do you have? Ideally it should be capable of 1200Amps SUSTAINED power output. These things suck the juice on start. A good powerful power unit will give you much quicker much cooler starts. Good news for the gen brushes, good news for the engines, and good news for the batteries (by the time the start sequence is complete, our batteries are fully recharged).