starter generator is driving me crazy
 

I have a starter generator that I have cleaned,new brush springs,and I have also repaired a field lead from somebody overtighting the terminal causing the lead to ground it'self out on the housing. The brushes are not that old. Not even halfway worn yet. So I put this thing on and go to jump it and it spins up but not that fast. I'm not sure if it spins fast or not. So I mount the starter on the kohler and it acts like it doesn't have enough power to spin up the motor. My question is are the starter generators supposed to spin fast? I'm stuck. I'm just trying to see if my motor will run but I can't get past this problem. I need help. Thanks devildog

Well, several questions. What are you using to "spin" it. A battery? Or a charger? Is the battery good, along with all connections and cables? How do you know you have a good armature? Good brushes don't mean anything if the armature has a dead circuit. They should spin fast enough to start a motor.... What motor? What tractor?