Truck Repair: N14 Over Reving

Question
Cummins N14 mechanical, industrial application, engine #475-2100.  Problem with the engine over reving,  it will go from 1500rpm's to 2100rpm's on it's own(that is without the turbo on, it will go from 1800 to 2400+ with turbo installed). Put new injection pump and STC valve on, checked fuel lines and ran off different fuel source, with the same results.  I'm in the process of checking injectors, not sure what else to do.

Thanks

Answer
I've never worked on a generator pack before but from what i know of them. There is something electrical that senses a load to cause the engine to rev up. I would start there. The only thing that would cause an overrev mechanically would be a leaking injector and a blowed turbo feeding the engine on oil but those would cause a runaway situation not just over revved.