Mark,

As Bill said, most of us have Onan's so we won't have any Norhern Lights specific knowledge or experience to assist you.  However, there are some common generator starting issues including a weak starter battery and corrosion on electrical terminals that you should check for.  A quick check for the battery is to start the main engine and then see if you can start the generator while the engine is running.  If you can, the likely culprit is a weak starter battery. 

--
Mark McGovern
SM #440 Cara
Annapolis, MD USA