Onan Micro 4000 Generator Won't Start

I'll check them when I get back, but the batteries were installed less than 6 months ago. I did check them for tightness, nothing seems loose.

Clean and tighten the battey terminals and ground wire. A little corrosion can make a difference.

I removed mine from my Class C, took the cover off, and found the positive feed to the battery was totally loose. Cleaned it up and it works just fine now.

It's a bit of a bugger to get the generator output wires pulled back. Find the electrical junction box first. I found mine inside the "insides" of the unit. The electrical flexible conduit with the wires in it came through the floor and into the metal junction box. The junction box was found inside the closet panel with opening doors on the top, but with a screwed panel over the bottom (what could be another shelf but contains pipes and the junction box) section of the cupboard.