Onan4000: Change Oil Filter?

[3dcal]

Hi,
I'm replacing the spark plug, fuel filter, and cleaning the carburetor
on our Onan 4000 in our 1999 Minnie Winnie.

We bought it 10 yrs ago, and have never replaced the oil filter.
I'm sure the oil filter needs replacing, but it must be so much hassle,
can't find any videos on it. LOL!

It looks like I have to take out the genset to get at the oil filter.
Any tips on how to unbolt it, and drag it out without breaking my back?
It weighs 174 lb. Maybe a pair of sawhorses to hold it?

Maybe cut a hole in the cover where the filter is???
You'd think they would make it easy to get to .
Or just forget it, and not bother with the oil filter?

 

[X-Roughneck Strike 3]

The 4000 is Oil Bath, meaning it just slings oil around while the engines is running to lubricate . There is no Oil filter to change. It Takes 1.6 qt of oil to fill. It does have a Air Filter you need to exchange when you are doing your maintenance. Engine is also Air Cooled.

Do Not NOT to overfill this unit. When you take out the dip stick and the oil is at proper level you will have the first thread wet on the screw in yellow oil cap. Don't overfill.

There is a eye shaped cover on the Lower plate the Gen Sits on. Look under that and that you will need to remove the bolt on one side of the access panel to drain plug and loosen to get at the Drain Plug (1/2" socket with Extension works perfect I think for Plug). You will need a Torx # 30? for the Dust Cover Plate.

Real easy job only takes a few minutes, and remember 1.6 Oil qt is MAX.

JD

 

[X-Roughneck Strike 3]

Air Filters for the 4K

Onan P/N: 140-3280

Wix P/N: WA 10165

 

[Gary RV_Wizard]

What Roughneck says! No oil filter, but you really need to change the oil and the air filter.

 

[3dcal]

Thanks, guys!

No oil filter, no wonder.
But that simplifies everything.

I'd let it sit too long without starting, and it's surging.
So am running 1/2 gal 91 octane + 1 can of SeaFoam through it per videos I saw.
I.e. unplugged gas line from fuel pump, and have 3ft fuel line to
1 gal can with SF & 91.

Just started the process yesterday, and let it run 5min to flush out
the old gas. Will cycle it today for 10 min at a time, with a few hours
in between to let the Seafoam work. I'll give it a few days before
Plan B, i.e. replace carb.

I bought a new carb for $38 at Amazon just in case. If it works, fine,
in not, will get the $300 ONAN.

The air filter is clean, but will replace the plug, and fuel filter.

Do you add Seafoam to each tank?
How many cans?

 

[darsben]

You have not changed oil in 10 years? WOW. With no oil filter or oil pump you have gotten very lucky IMO

 

[3dcal]

"We bought it 10 yrs ago, and have never replaced the oil filter."
Yes, have changed the oil a few times since.

Ran the genny today for 15 min.....surged the first 2 min, then
evened out, but not perfect yet.
Better than it was, though. Will keep at it.

 

[DonTom]

Do you add Seafoam to each tank?

There is no reason for additives if all else is fine.

BTW, Amazon also sells the complete tune up kit for our 4K generators.

Mine is a Onan 4.0 KY-FA/26100 J. What model is yours?

I recently put in that same $38.00 carb in my Onan. I gave it a five star review on Amazon. It works perfectly. My Onan broke while running. The pin that goes to the butterfly valve from the control level broke inside my Oran carburetor while the generator was running. Seems to me that the $38.00 carb is better built than my Onan OEM was.

No oil filter. Always screw the dipstick in all the way to check the oil level. And fill BELOW the full mark. Some of these generators are flakey when filled to the full line.

-Don- Auburn, CA

 

[3dcal]

Hey, Don.
Thanks for the video!
Will make sure not to overfill.
I bought that tuneup kit, too.
My Onan is same model as yours.
I think replacing the plug & fuel filter will help.

Glad I didn't take it in to the shop!

 

[DonTom]

Glad I didn't take it in to the shop!

I change my generator oil once per year at the same time I change the RV engine oil. Usually in April or May.

The older Onans use an oil filter. The newer ones (includes ours) run much cleaner and so no oil filter is required.

One more item I strongly recommend is one of these.

That way you can tell if your generator is on frequency and has the proper voltage under various loads.

It really came in handy for my generator to make some minor adjustments after I replaced my carburetor. Light loads such as converter only are right at 60 hz mostly, but plus or minus 1 hz. Varies 1 hz or two hz from 60 (58 to 62 HZ) with various loads from moderate to heavy, which is close enough to run anything correctly.

BTW, I adjusted my carb to go leaner faster with the new carb. It wanted to stay rich a little too long, even after I replaced my torn choke heater tube. The one minor easy adjustment made it work perfectly from a cold start to full warmup.

I have done nothing to it other than change the engine oil until mine broke down a couple of months ago when I was in Organ Pipe Cactus National Monument, AZ where I needed it the most.

Since then, I have done a lot of work on it and I now have it running better than ever. I leaned a lot about how it works in the last month. I even removed it from the RV for a few days to work on it. The entire story is here.

-Don- Auburn, CA

 

[X-Roughneck Strike 3]

I change my generator oil once per year at the same time I change the RV engine oil. Usually in April or May.

The older Onans use an oil filter. The newer ones (includes ours) run much cleaner and so no oil filter is required.

One more item I strongly recommend is one of these.

That way you can tell if your generator is on frequency and has the proper voltage under various loads.

It really came in handy for my generator to make some minor adjustments after I replaced my carburetor. Light loads such as converter only are right at 60 hz mostly, but plus or minus 1 hz. Varies 1 hz or two hz from 60 (58 to 62 HZ) with various loads from moderate to heavy, which is close enough to run anything correctly.

BTW, I adjusted my carb to go leaner faster with the new carb. It wanted to stay rich a little too long, even after I replaced my torn choke heater tube. The one minor easy adjustment made it work perfectly from a cold start to full warmup.

I have done nothing to it other than change the engine oil until mine broke down a couple of months ago when I was in Organ Pipe Cactus National Monument, AZ where I needed it the most.

Since then, I have done a lot of work on it and I now have it running better than ever. I leaned a lot about how it works in the last month. I even removed it from the RV for a few days to work on it. The entire story is here.

-Don- Auburn, CA

The Power of the masses. Never underestimate people working together to resolve issues.

This is why I love being a part of RV Forum.

I run my generator each month, just because it is right here in the back yard and wanting to exercise the floats etc, keep the working parts...working.

Don, BTW.. Loved the link to the Industrial 4th Revolution, Fishducky story. So True!

JD

 

[3dcal]

Don,
thanks for all the great info. I'll probably get the AC Monitor.

I started the genny this morning.....it took a while to prime it,
then crank it a few times before it got going.
It was surging again. I let it go a few minutes, then thought
I'd make a video so you could hear it, so stopped it, took 5min
to get my camera, and then couldn't start it after priming 20 sec,
and then with 15 sec 4X.
May have flooded it.

Didn't want to run down the battery, so will give it a rest until tomorrow.
I'll replace the plug before trying to start it again. Also need to clamp
the tubing just above the can, so I don't lose the column of fuel, and have to prime
more.

What's ironic is we rarely use the house generator, except for air conditioning.
We use a litte Honda 2000 for 95% of our electricity.
But "better to have it and not need it, than to need it and not have it", as the
bails bondsman said.

 

[DonTom]

It was surging again.

It could be normal. Without knowing the frequency you will not know. The governor tries to keep it at exactly ( within a few RPMs of) 3600 RPMS, so when it starts to slow a little the governor makes it increase a bit trying to stay at that 3600 RPMS for that 60 hz.

Look at the top of the carburetor to see what it is doing when running from the linkage. That is what you're hearing.

If there is anything seriously wrong, the control board will shut down your generator. Stuff such as too high or low of a frequency or voltage. I would not be a bit concerned about the generator sound if the frequency and voltage is steady. And if it's not shutting down, it has to be at least somewhat within reason, no matter what you hear.

Every 60 RPM equals one hz.

So every 600 RPMs is ten hz.

Six times that is 3,600 RPMs for 60 hz. Unlike a car engine, and unlike an inverter generator, your Onan MUST run at 3600 RPMs at all times, cold or hot.

So from an ice cold start it should run at 3,600 RPMs the same as when it is very hot.

Nothing like a car engine, with the cold faster idle and such.

An inverter generator (NOT our Onans) can run at any speed, because it is converted to DC and back to AC again by the internal inverter. So also do not compare to those.

Don't expect it to sound as steady as a vehicle's engine. The important thing is that steady 60 hz within about two hz.

My generator has been running for the last two hours. My final test, with a load of around 2,500 watts. RV refrigerator, converter charging back up the house battery and a 1,500 watt tower heater. I decided to run it for two hours now that I have the cover on, just because that is what they allow at Organ Pipe Cactus National Monument (two hours twice per day, once morning, once late afternoon). The 1,500 watt heater draws the same current as my electric motorcycle.

It doesn't sound steady, but it works perfectly and that is all I care about. Steady 60 hz and 119 volts the last time I checked it, just before tying this message. But the engine doesn't sound steady, nor do I have a reason to want hear such.

Now, I will turn off my generator. It has been running perfectly for the last 2.5 hours with a moderate load.

-Don- Auburn, CA

 

[3dcal]

All great info, thanks!
I've neglected the house genny too long, & am paying the price,
but will make sure to stay on top of it from now on.

 

[DonTom]

All great info, thanks!
I've neglected the house genny too long, & am paying the price,
but will make sure to stay on top of it from now on.

Other than changing its oil every year, I did exactly the same until mine broke down.

BTW, one more maintenance thing you should do every so often.

When your generator is cool . . .

On the bottom of your generator muffler, you will see two square bolts. An 11 MM opened end wrench should work to remove them if they are not too tight (and they get very tight if they have never been removed!!!),

After you have them both removed, run the generator under heavy AC load (more than 2,000 watts or above 18 amps at 120 VAC, the more the better until 4,000 watts) for around ten minutes or so.

Job is then complete, other than putting the two bolts back in after the generator cools down.

Doing the above, will get the soot out of your muffler.

-Don-

 

[3dcal]

Just replaced the plug (what a PITA getting it in!)....
bad news.....wet. =()
Tried to start it.....primed 15 sec, cranked 4x5 sec, but didn't want to
run.
What next? Ring job?

 

[DonTom]

Just replaced the plug (what a PITA getting it in!)....
bad news.....wet. =()
Tried to start it.....primed 15 sec, cranked 4x5 sec, but didn't want to
run.
What next? Ring job?

No, you have a simple problem. Running way too rich, getting way too much gasoline on the spark plug. Try not priming at all, in fact, I would let the carb run dry first by pinching the fuel line (there are cheap tools for this that you can buy at any auto parts store) pinching and and trying to start. Then put everything back to normal, first trying to start without priming at all.

-Don- Auburn, CA

 

[3dcal]

Hey Don,
You were right it was fuel, not oil, or a mixture of both.

I let it sit overnight, then tried starting without priming.
It fired up right off the bat.
I let it run dry, then plugged it into the hi-test/Seafoam mix,
primed it 15 sec, but couldn't get to start. %$#&!!

I'm done with it. I decided to take it to a place that only works on
generators, Quality RV in El Cajon, Ca. on March 3.
They'll diagnose it, and see if they can tweak it, e.g. the mix, or linkage,
but if necessary, will replace the carb with an ONAN 4K.
They'll also test the pressure in the fuel line & pump to see if they
need replacing. I have the parts & they'll "throw it in".

I could probably do myself, but at this point am tired of messing with it,
and will just let the pros do it. Life is too short.
It will cost $165-$600 depending on what they have to do
(plus $40 for gas for the 100 mi round trip)

I already replaced the plug, and will change the oil ahead of time.
Have already returned the $38 carb & unnecessary oil filter to
Amazon.....will pay for the gas!

I'll maintain it from now on....my wife will make sure!
She was a supervisor, and has a whip. LOL!

If you didn't get a good laugh out of all that,
here's one for the road.

Thanks for all the great info & help!

 

[DonTom]

I let it run dry, then plugged it into the hi-test/Seafoam mix,
primed it 15 sec, but couldn't get to start. %$#&!!

Most likely, you over primed again. Try letting it sit over night again. If that doesn't work, remove the spark plug and dry it (and perhaps clean it).

If you really got all the gas out of carb, and need to prime, use only a second or two at first. The idea is do not flood the carb. Only use the prime as little as possible. For normal operation, do not use "prime" at all.

IOW, only use prime when the carb is out of gas for a known reason.

Removing the generator and bringing it to a shop is a lot more work than the simple fix ( most likely).

-Don- Auburn, CA

 

[3dcal]

Removing the generator and bringing it to a shop is a lot more work than the simple fix ( most likely

Yeah, 174 lb too much to deal with.
That's why I'm driving down there, and they'll get it done in
1hr. Worth it to me. Cheaper than back surgery.
I'll be careful not to flood it when starting, though.