In the motor area, rear left side, where the original mechanical voltage/current regulator was, I have an electronic regulator. In the regulator, I have 2 wires: excitation, that comes from the alternator, and +, that is live when you open the contact with the key. I wired the red wire there, so the pump starts when the contact is set. The black wire is set to GND. The electronic regulator also releases the inner 6mm bolt, because it is smaller than the original, so there I fixed the pump. I strongly suggest to put a fuse inline, just in case.
So: Tank -> filter -> pump -> carb