Lots of problems here, lots of trickle out info. Including 12V conversion. Someone has taken some sort of a starter and tried to make some sort of a starter. I hope you can show us the armature number you see stamped on it becasue it's not a 1867897. I hope you didn't just give that number from another source. If it is stamped, it's been modified. Also, obviously they didn't use hardware store washers as spacers.
The starter is a DIY messed up wan-a-be 12V starter and needs to be abandoned. THERE IS NO MORE DIY left in it. Buy a proper starter for what motor, ring gear and voltage you have.
