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Minnesota51 · 03-21-2019, 11:46 AM

On the road this spring, had generator starting issues with our Microquiet 4000KY generator.

At a Cummins/Onan Service Center, the technician told me that even if you run your generator 2 hours a month in storage, these carburetors can still gum up. He said it is so common they call it the "4000KY Blues' and some people are at the show every spring spending hundreds of dollars to have the carbs cleaned.

He said you can easily drain the fuel from the carb bowl when you store it and the problems will disappear. He showed me how to use a screw driver to drain the gas, into a flat circular container (he used half of an electrical tape case).

It took 30 seconds.

Then you don't have to run it every month.

When you want to start the engine after doing this, hold the "prime" position until you hear the fuel pump quiet down meaning there is gas in the carb again and the float has shut off the gas coming in from the pump.

Then start it. It fired right up again.

He said unleaded gasoline today cannot be trusted to sit in these 4000KY carbs in storage without sometimes closing that TINY jet opening enough to give you starting or running problems. Even if you run it a couple of hours every four weeks.

So simply drain it in storage.

I asked about running it to keep moisture out of the coils. He said it really wasn't a concern. Seems like starting it every month and running it under half load is all about the carburetor jets.

Gary RVRoamer · 03-21-2019, 02:18 PM

The card isn't the only reason for regular genset exercise. Onan wants it to get hot enough to bake out all the moisture that may accumulate in the stator and armature. Obviously that is a larger concern in humid climates than dry ones, so your mileage may vary.

gljurczyk · 03-21-2019, 04:35 PM

You are very correct for the reason to heat them up, as far as draining the carb. Yes that will work,.but I have never read or seen that happening if you run it monthly as they recommend, plus if I was really worried I would just add some additive or something at every full tank. That will keep that garbage gas fresh. I would like to see that in In A onan manual and not take the word of a tech. Everyone has a opinion I guess including me. SHOW IT TO ME IN WRITING.

chuckftboy · 03-21-2019, 08:27 PM

I have a gas gen for my home. its an 8500 and I only use it once every year or 2 when a hurricane takes the power out. bought it 14 years ago, drain all the crap fuel after every use and it hasn't failed me in 14 years. Starts on the first pull every time.

avfordguy · 03-21-2019, 11:07 PM

I dont run mine every month, just drain the carb fuel bowl, if surging starts I run heavy mixture of seafoam in a dedicated fuel source , then drain float bowl, good YouTube video on it.

avfordguy · 03-21-2019, 11:08 PM

Forgot to ad, that it's a 2007 model 4k onan microlite.

Tha_Rooster · 03-22-2019, 05:03 AM

How about putting stabil in tank to protect engine and genny?

ScoobyDoo · 03-22-2019, 05:27 AM

From my teens I have been taught to drain a carb unless I know I'm going to be using it in a couple of weeks. On old cars that I know will not be driven much, I put a valve to shut the fuel off, let the engine idle until it dies. Back on the farm, when put the combine away, clamp the fuel line on it and the truck with vice grips...

BirchyBoy · 03-22-2019, 05:30 AM

OP - can you describe the process?

Offramp · 03-22-2019, 07:02 PM

I get what you are saying Minnesota51. And will confirm your techs comments about draining the carb.

Old-Biscuit · 03-22-2019, 07:10 PM

True statement about the gasoline....never quite know what is in it

That is why I use Seafoam or Stabil in ALL my gas cans....which then is used in my generator/lawnmower etc

As for exercising gen.....
Yes it helps flow old gas out/new treated gas in
BUT main thing is to bring stator/rotor/windings up to temp and get rid of any moisture that can be present.

My gen starts within first few cranks everytime.......lawnmower too

Mudfrog · 03-22-2019, 09:03 PM

Quote:

Originally Posted by Old-Biscuit

True statement about the gasoline....never quite know what is in it

That is why I use Seafoam or Stabil in ALL my gas cans....which then is used in my generator/lawnmower etc

As for exercising gen.....
Yes it helps flow old gas out/new treated gas in
BUT main thing is to bring stator/rotor/windings up to temp and get rid of any moisture that can be present.

My gen starts within first few cranks everytime.......lawnmower too

And at the same time,, I have never used a fuel additive and have never had a problem. For probably 12 years, I only ran the motorhome genset when I needed it. It would sit for months sometimes before the next crank. I do now run it monthly and it always starts on the first or 2nd try.

The lawn tractor, push mower, four wheelers, and 4 stroke boat motor all have times when they sit for months between starts. No problems with them either. I don't know, maybe I've just been lucky.

Minnesota51 · 03-23-2019, 12:15 AM

Quote:

Originally Posted by BirchyBoy

OP - can you describe the process?

It's pretty simple. There is a screw on the carb, on the bottom beneath the fuel bowl. Turning that opens the drain and lets gas run out into a container you would hold under there.

I bet there is a video on youtube for doing this for the Microlite 4000 KY genset.

Teamfoxy · 03-23-2019, 06:16 AM

Draining the carburetor is good, but you also get buildup in the fuel pump and lines from fuel that sits. That all winds up in the carburetor. When I took apart my caruretor for cleaning, after purchasing the last RV, there was a buildup of crud in the sensor/cutoff switch at the bottom of the bowl. Draining the bowl would not remove gas from the sensor.
I like running the seafoam treatment (using non-ethinol gas) from a separate container several times per year. I run a seafoam/non-ethinol gas mix in all my yard equipment and never have a problem with any of them.