If you have power on the dark blue wire, it should at least start while the key is in the start position, If it doesn't then you need to check the pickup first, then move the the control unit. I check the pickup initially by getting it to a spot where I can move the rotor against the mechanical advance weights, back and forth while one of the 8 points on the reluctor passes past the pickup's metal point. This should cause a spark when your coil wire is held close to ground. It should spark everytime you wobble the rotor.
Try that 1st
When you say that it starts when releasing key, I bet it doesn't really start. I bet you mean that it "fires" then doesn't start, right? That is just caused by a spark that is generated when you release the key, when the coil's magnetic field collapses. It fires a random spark plug and the engine seems to try to start.
Rob