starter still cranks while key is off

[jeff5347]

Ok after reading some starter probs came up with no solution to my prob. Current setup:
battery in trunk with ford style solinoid mounted on batt box
Power master hi torque mini starter
Shutoff swith in the license plate

My problem is if there isnt enough juice in the battery and i try to crank it sometimes it just clicks which i know just means not enough juice to crank. What also happens occasionally is if not enough juice the starter will crank very slowly and when i shut the ignition off and take the key out the starter is still cranking slowly. What give if ther is no ignition cranking it? It has happened before the kill switch. to stop it from cranking i can use the kill switch and no more power. What gives