Stator failure cause?

I am in the process of replacing my 5th gen stator that has 61,000 miles on it.  I think that would be considered a long stator life, but I really don't know why it gradually failed to produce adequate power, for the following reasons.

1.  The Stator coils are ungrounded and showing no continuity.

2.  Stator field resistance shows within spec .5 ohm on all three fields.

So if the stator is not shorted out/grounding and the field coils have normal pathway resistance, why would it not produce power as designed?  

This question leads me to this proposition.  Half of the coils sit in motor oil and this causes a semi crusty baked on oil buildup.  Could the baked on oil build up somehow cause a weaker magnetism transfer (or flux leak) to the coils?  If that was the case, possibly removing the carbon buildup on the coils would solve the problem.  I might giver that a try just to satisfy my curiosity. 

Any other ideas why the stator fails when it should be good?

Perhaps test your output voltage...... regulator disconnected.  I suspect you have a regulator/wiring issue.  Stator might look a little cooked, but may not be bad. 

I'm not so sure it's in constant bath of oil, just oil splash....  I wouldn't risk removing "the carbon"...

Post a pic, it's hard to know what you have.  If it's black, it may be cooked, but it's testing ok so far.

I ran a voltage output test with one of the 3 coil combinations at a very low 1v at idle, 3v at 3k, and 4v at 5k.  The two other combinations were ok at 58v at 5k.  As before, if it isn't shorted out and the wire resistance is normal, what would cause the stator to not perform.   When I get my cover gasket the plan is to clean off the oil crust buildup at the coil ends nearest the rotor and do a quick reinstall to see if that is the issue.  I will post my findings.