Marx Universal Motor

I have a Marx 999 that will run for a few minuets and then start to slow down and finally stop. I've cleaned the armature and commutator which seamed to boost its power a little but not the run time. I'm suspicious of the stator windings. The windings are newer looking ( copper colored ) and spliced at one end by a soldered piece of magnet wire. The armature has the black enamel coating on its wires and checks out with an ohm meter at all 3 poles. I think this was a failed rewind of the stator. I would like to know if any one knows how many turns it should have and what AWG the stator wire should be.