starter motor wiring

[E30Charlie]

Right finally got the m50 running thanks to some wiring help from dan and will, cheers guys.

now im using the m20 starter, has 3 terminals, the m8 sized terminal in the middle a normal sized spade terminal at the bottom and a smaller spade on top.
the m50 starter had 3 terminals but all studed ones, so i just changed the connectors and connected it all up, big wire 2 big terminal, medium to medium ect..
when i tryed 2 start it, the starter wouldnt disengage, had 2 disconnect battery 2 stop it, also no sign of fuel pump or firing.
so i disconnected the top (smaller spade terminal) wire and cranks and stops off the ignition and after a few cranks she fired up. why was this and what do i do with the now unattached wire?