Originally Posted by pimpernell

Now, when you describe 4 or 5 cranks, we need to know the duration of each crank. It is not recommended to crank the starter more than 35-45 seconds at a time, with 4-5 minutes between cranks, so that the starter does not overheat. From what you describe regarding the mechanic using 4 batteries, it looks like they may have overheated the starter to the point of breaking down the insulation, and causing the the copper wires to become brittle. If that is the case, I would recommend having the armature checked at a competent re builder to see if it can be salvaged. If not, you may have to replace it with a new or rebuilt one. Good luck