I think that it is worth it. We are both experienced mechanics and he serviced and repaired gen sets as part of his duties at a previous job. If it ends up being the stator/rotor and cost $2k he is still a couple grand ahead of a new set. And if it doesn't work out we will part it out.Hopefully its not. One thing not worth replacing is rotor and stator set.
I just have a hard time believing that the rotor/stator would go bad on such a low hour machine. We'll see.