If you had full voltage in the brown (solenoid) wire to the small terminal (from either the starter large terminal or above from the SR) it would be cranking just like normal operation. As you know the large cable is hot all the time & it almost sounds like some current is bleeding over inside the starter to (likely) the hold in solenoid winding and that is the minor draw (if it was the "pull in" solenoid winding the solenoid rod would be pulled in & the starter would be cranking like normal & you'd have to pull a batt cable to stop it. Holler how it turns out