Onan Micro 4000 Generator Won't Start

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.

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

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.

txnese wrote:
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 the terminals. If I get a (very) little corrosion on the battery terminals, my 96 Southwind won't start. Same as the Onan 5000.
Clean them to make sure.

are you checking both the house and the chassis batteries? which does your generator use?

Another thing. My MH has a switch right next to the step under which the house batteries are stored. That switch turns the house batteries ON. Without it on it acts just like you're saying. I have gone around the horn a few times before I realized my error.

In my situation I was plugged into shore power and the charger produced enough juice to light up and click but not enough to crank the genny (no surprise).

Mine has wire on sideniod that doesn't always make good connection. I have to clean connection and then good to go. I even have a paper clip under Male side of spade type connector.

txnese wrote:
I'll check them when I get back, but the batteries were installed less than 6 months ago. .

I think you are assuming too much here. The batteries could have been installed yesterday and if not done right, the connections could be bad today.

And how do you KNOW that the batteries have a full charge.

If it sounds like the batteries are weak, then they probably ARE....or the connections are bad somewhere. Do not assume anything.

One trick in startin generator is to fire up the rv engine - that places both the chassis and coach batteries in parallel - should provide you with maximum DC for starting up generator. As others have said - clean the positive/ground connections on batteries and generator.

The chassis engine fires right up, so that battery is good. I checked the house batteries with a volt meter and it reads about 12.6 volts. I also checked the generator's starter relay, got 12 volts on input side, and 0 on the output side. I push to start the generator and the output side shows like 4 volts. I was thinking bad starter solenoid, so I used a starter jumper switch to give the output side 12 volts and nothing still happens. I would replace the starter itself, but the light on the button is dim. I almost want to blame the control board, but don't know enough to condemn it. I'll do some checking in the morning. Just doing what I can before I turn it over to an RV shop.