What is the point setting and spark plug gap for the onan's generator built by studebaker?

Basic setting for most engines are 15 thousands for points and 30 for plugs.

Plugs = .030 inch.
Point Gap = .015 inch. Frequently, the cover plate can be removed and used as a feeler gauge for the points.

Google your Onan generator's model number for more information.
I remember carrying a match book: the cover was just about .015 and the striker could be used to burnish the contacts, too. (wow... that's been a while.. )