@Stig how exactly did you disconnect the wires from the old pump without desoldering? Did you simply cut the wires?
Perhaps you can see from my original photos of my pump - wires to pump were pressed on spade connectors....no solder was used by Kymco at that time, nor by me in my rebuild.
If there is some solder on your wire connections to the pump -
you could heat and remove them PROBABLY NOT A GOOD IDEA IF FUEL REMAINS IN THE PUMP TO GO NEAR IT WITH HEAT!....or unscrew the other end of the 2 wires and then rebuild and copy the original connections with wire & a couple of bits from hardware store.
I'm losing the thread here - you are replacing the pump because you are not satisfied with the spray
pattern or strength from the injector when cranking the scooter and spraying into a can?
Stig