Onan Microquiet 4000 Won't Turn Off

Fuel cutoff will cost you less than $5.

Could be the board but if you don’t want to spend the money like I wouldn’t I would put a in-line cutoff in the fuel line . Cut the fuel off till it dies.
It’ll clear the fuel out of the bowl to.

When it happened to me, I had to replace the control board. I took some pliers and pinched the fuel line closed to kill the generator.

google your problem, might be some help there.

naturist wrote:
My money is on a bug that sought cover in the switch and died between the contacts.

Since this affects both the inside and outside switches (the one in the RV and the one on the generator itself), it would have to be two bugs that crawled into the same spot of both switches at about the same time and there died. Seems a bit unlikely to me.

Besides the control board, it could be a loose or ill-connecting wire inside the generator. It would not hurt to unplug and replug the connectors that mount to the generators "firewall", maybe hitting them with some contact cleaner in the process. I would not hold out too much hope for it working, but at the cost of getting and putting in a new control board, it's certainly worth trying.

My money is on a bug that sought cover in the switch and died between the contacts.

What is the full model and spec number of your genny.(so I know which control board it uses) Onan starts and stops by switching grounds to control board. the center terminal or common terminal on the switches is grounded.
So if unit starts ok, you know that the ground circuit is ok.
If it will not shut down from either switch location, then likely problem is control board.
another possibility is that the "kill" wire to ignition magneto has come loose, preventing the control board and both switches from stopping the engine

Hmmm...well, I don't know anything about the specific wiring of your generator, and I'm sure it'll depend upon the age & model of your generator, but the majority of the small engines I've worked on shut down by providing a ground to the ignition circuit.

I'd look carefully for any ground wires or connectors associated with the generator and clean them up to make sure all connections are clean and tight.

Good Luck,

~Rick