Kohler 5.5 marine generator not charging

Its broke... take it to someone to fix it. Or buy a service manual and try it yourself.

Hi,
I hope you realize that it is impossible to answer except generally without such info as model. At any rate the technical document landing page for KohlerPower is at:
Kohler Power: Technical Documents: Technical Library: Industrial Generators (http://kohlerpower.com/industrial/technicaldocuments.htm?sectionNumber=13261&nodeNumber=4&contentNumber=301)
Peace,
Clarke