Ok, for the first time now, I could start the B747-400 engines.The problem was that every time I turned ON the hydrolic pump number 1, this one never turned himself ON i don't know why.However, by switching all the hydrolic pumps ON except the 4th, and then open the engine bleed air valves, the hydraulic pump 1 was working. And as a result of it, I could finnaly pull the black nob on the overhead panel with success.Thanks for your help,Francisco Saraiva