Onan Micro Quiet 4000 Gas Powered Generator Won't Crank

What's its fuel source? My generator gets its fuel from the RVs gas and the system stops it from starting when my RV fuel tank is below 1/4 full.

Other usual problem is enough fuel in the system. You have to prime the heaven out of small generators some times to get them to start.

Boy, did that take a long time to figure out.

Open generator shroud on the ONAN cover (with the two flip latches). You can reach the flywheel pretty easily from the left side; it's basically in line with the vertical baffle in the generator case.

Check the voltage at the generator when trying to crank, and in particular across the starter solenoid. It may be as simple as a bad connection there, or a loose control wire on the solenoid. Hopefully it's not the starter itself or a connection to it as you need to entirely remove the upper generator case, which generally means dropping the generator. On my Coachmen, it took me a good portion of a day to disconnect the necessary connections and drop the generator (to change out a broken starter).

In the past when the house battery was too weak to start my Onan MQ4000 I would:
1) start the MH's engine
2) go back to the test panel
3) push down on the generator rocker switch to prime it
4) push up on the generator rocker switch to start it
5) turn off the MH's engine

I'm not sure why it works, but it does on my MH. YMMV


EDIT: had the "down" and "up" reversed

Can't add much to the above, except I've found the Coach/House Battery has to be in TOP condition to crank that little ONAN. I know that suggests that Engine Running + Emergency Start, should crank it. Still wanted to mention my experience.

Taking this as Reminder to go exercise our genny.

Can somebody provide the Wrench Type/Size our OP should try on that Flywheel?

I had a similar problem with our Onan MicroQuiet several years back. We had pulled into a gas station and shut down the generator without letting it run for a few minutes with no load to cool down. When we tried to start it later the starter clicked but it wouldn't crank at all. I removed the generator access cover, reached in and tried to turn it by pulling on the fan blades. No luck with that. Fortunately I carry a 3/8" socket set that had the right size socket for the bolt on the fan/flywheel. It took quite a bit of effort to break it free. Started right up with the starter after doing that and no problems since.

I'll never forget the no load cool down period again!

I've just reached in with my hand and (carefully) twisted the fan blades on the edge of the flywheel. No idea what the big nut in the middle is for the Onan flywheel. Obviously one wants to take care to avoid starting it inadvertently.

I would add: before moving the flywheel, disconnect the negative cable on the battery. Murphy's Law (Anything that CAN go wrong, WILL) states that moving the flywheel will start the engine.

UPDATES:

1. Socket Size is 9/16" with a snug fit and 14mm will also work

2. It's easy to get a socket in there on an ordinary ratchet

3. Our 4 YOA Walmart trolling motor battery 1 year warranty is failing

4. I was able to start the generator by clipping one of those little Lithium Ion start packs. Specifically a Stanley SmartStart

CloudDriver wrote:
I had a similar problem with our Onan MicroQuiet several years back. We had pulled into a gas station and shut down the generator without letting it run for a few minutes with no load to cool down. When we tried to start it later the starter clicked but it wouldn't crank at all. I removed the generator access cover, reached in and tried to turn it by pulling on the fan blades. No luck with that. Fortunately I carry a 3/8" socket set that had the right size socket for the bolt on the fan/flywheel. It took quite a bit of effort to break it free. Started right up with the starter after doing that and no problems since.

I'll never forget the no load cool down period again!

I am not familiar with a no load cool down and having to turn your gasoline engine to break it free, break it free from what? If your gasoline engine is locked up and won't turn you have some serious issues, how does heat lock up your engine preventing it from starting again? This is a new one.

So did it end up being just a low battery, or was the TDC thing the culprit?