Lazy Daze Owners' Group

It was running fine on the monthly exercise. And then it didn't

I would really like to avoid an overnight trip to the Cummins dealer. So I am again asking for help.

I posted about this last month and got several suggestions. Alas, all missed the part that the generator was pumping fuel. I can disconnect the fuel line from the carburetor, hold down the prime switch and it will pump gas as long as I hold the switch down. I would say this eliminates the hose having air leaks and also the fuel pump as a culprits.

Observations:

When priming the light stays on forever. It should go out after a few seconds indicating it's primed. Sensor to the control board?

It will start if I use starting fluid and stay running as long I inject starting fluid.

When it stops after using starting fluid, it WAS showing a code. I misread it and now it does not show a code.

Any ideas? Carb? Control board?  Both were replaced a few years back.

If it runs with starting fluid and does not without it then it has to be fuel? My prime light stays on as long as the prime button is pushed.

Need to check if fuel is pumped when start button is pushed? Check for power to pump when start button is pushed?

Hey Don,

First thing I would do is pull the sparkplug to see how it looks. I realize it runs on starting fluid but I would check the plug or install a new one. Then I would flex the throttle linkage to see if it is stuck. Also check to see that the choke plate is not stuck closed.

Good luck with this. I too hate the visit to the Cummins doctor.

Steve K

There is an oil sensor that will shut off the engine if it thinks (actual or in error) that the generator is short on oil.

I find that the Onan manual has a decent troubleshooting guide.  It's been helpful to me in the past.

Rich

I would say this eliminates the hose having air leaks and also the fuel pump as a culprits.

If it were me, I would run the generator off a small jar of fuel for a while to see if I could replicate the issue. 

It is possible to pump fuel with a air leak somewhere along the path.  This happened to me when some mice chewed a nice hole in the plastic fuel hose. 

If you can get it running off of a local fuel source, you can take that opportunity to run some carb cleaner (sea foam or whatever) through the system. 

Rich

If Carb..  Needle as seat stuck not allowing the pumped fuel in?

Do these generators have a fuel cut off solenoid on the bottom of the float bowl. If so, they do stick closed on occasion or your just out right flooded. New plug?

Thanks for all the ideas. I will run them down as soon as the driveway dries out.

I should have mentioned it's MicroQuiet 4000.

I just went out and removed what I take to be the drain for bowl. Not a drop came out. See picture, I took the silver screw out. Is that the bowl drain?

So while fuel is being presented to the carb, it appears none is getting in.

Seems to me that I once knew to drain the bowl for storage. SO while I was cranking it once a month, over the long period it's been in the driveway it must have gotten junked up.

This YouTube video is quite helpful. Thanks Ramon

Don, 

I think you have the 4k unit with the plastic  green case around it?    Oh,
see you posted that now.   I have more familiarity with the older non
microquiets but they should all work the same though you have codes.  Too
bad you can't get that code again.  The fact that it runs on starting fluid
means it not getting fuel.  Based on your posts, sounds like you have
enough access with the gen door off.   If there is a drain screw on the
float bowl, bottom of the carb, you can drain it out, leave the port open
(does it have a hose connected, or can you connect one to catch fuel).
With the drain screw open you can run the prime button and see if the fuel
come out .  If the needle attached to the float is stuck closed, fuel will
not fill the bowl and drain out.   Here is a video of how it works...
[Link](https://www.youtube.com/watch?v=2ow9hwutC8A)  about the first 3
minutes.  you probably have a donut float instead of the barrel.  

And here is the actual unit...  [Link](https://www.youtube
.com/watch?v=fIlZTkBO5M8)     says there is a shutoff valve and gets stuck
so a little more involved that a regular carb float bowl.   Says there is a
drain screw.  If you open it an nothing comes out..  then might be the
stuck seat issue.  He says the float bowl seal can leak after you open it
and he does not say if you can get just the seal.

There is a chance the fuel shutoff valve is not being sent the signal to
open.  I would think upon cranking, this would get some DC voltage that you
could measure to see if it gets that.  Measure while disconnected.  Is
there a start switch at the gen?  Might need a second person.    Actually I
see it in the video now.   Oh wow, he just said not oil filter on these?
My early 90s 4k had a filter.

Hope this helps,  

Ramon

Have you replaced the fuel filter?

A few years back, Ross. If it were clogged it would not pump gas. I am more and more thinking it's the carb. Which has already been replaced once.

Today

Review, file is pumped out of the hose. Enough drops of fuel get into the carb to start it. It starts quickly and runs for 2-3 seconds.

If the carb drain is the silver screw in the photo above, no fuel comes out of it while being primed or when started. If I touch the drain with my finger it is ever so slightly moist. Please confirm that this is the bowl drain.

If the solenoid is the thing in the picture above that is below the silver screw, I read it getting 8v when cranked. Removing would be a PIA, starting with buying whatever size open end wrench that is one or sizes larger than 9/16. And of course it could be metric. Access to it is limited.

What is the function of the solenoid?

How does one check for the choke plate being stuck? What I would call butterfly valves on the top of the carb move freely by hand and go back and forth when the engine starts like they are possessed.

I checked and cleaned the spark plug.

It is back to throwing a code. Three blinks when it stops. Pressing the Stop button gives three more blinks. A 3-3 code is NOT in the manual. However on the generator is a label that states a 3 code (not 3-3, but it that my be shorthand) indicates Service Required.

Larry Wade wrote the other day that the fuel supply line was hard in the middle. They must have been out of steel tubing the day this one was built as it's rubber from the generator back to at least the leaf springs. I can not see after that. Need a lift. If only I lived close to Mike C.

Don the silver screw is the float bowl drain and the fuel cutoff solenoid is directly below the drain screw. Those fuel cutoff solenoids do stick as well as the float, That fuel solenoid has to energize to allow fuel in the float bowl. Like it or not, I bet the carb is going to have to come off if there is fuel to the carb inlet. I think there is a fuel flow spec somewhere. Free flowing out of the fuel line with the fuel pump running ( pump prime), you should get some significant gasoline.

Jon

Don the silver screw is the float bowl drain and the fuel cutoff solenoid is directly below the drain screw. Those fuel cutoff solenoids do stick as well as the float, That fuel solenoid has to energize to allow fuel in the float bowl. Like it or not, I bet the carb is going to have to come off if there is fuel to the carb inlet. I think there is a fuel flow spec somewhere. Free flowing out of the fuel line with the fuel pump running ( pump prime), you should get some significant gasoline.

Jon

It took me awhile to figure out who JONS was.
Hello Mr S,

Thanks for the confirmation.

Yes, it pumps significant fuel out of the line.
The solenoid gets 8V. Not sure how much it needs. Since there is no fuel in the bowl, the solenoid might well be the problem.
I think I have enough info now to see if a local mechanic could do it.

OR

I could try replacing the solenoid myself.

If that is not a cure then it has to be the carb.

Thanks

It's a delightful day here in Montgomery.

Don,

Another good video, addressing the Solenoid.  Though he takes the bowl off and the last RV tech said these tend to leak after you separate them. 

https://www.youtube.com/watch?v=xTekK7p7un8

He's getting 13+ volts at the solenoid but when priming, not cranking.  8 volts does not sound like enough even when cranking.

Ramon

Really good video. Thanks. I subscribed to this guy.
jor

Don,

He's getting 13+ volts at the solenoid but when priming, not cranking.  8 volts does not sound like enough even when cranking.

Ramon

This is great! Showed how to remove the solenoid simply by removing some things that are in the way.
I will try this at first opportunity.
Many thanks, Ramon

I will put these videos in The Companion

Hi Ramon, Thanks for that video.  It was clear and concise. The photography was well lit, not obscured. Clear, not out of focus on the closeups, and complete. He included a lot of information, and cautions at appropriate times. The explanation of the crush washers was the first I've ever actually seen. He "Knows his stuff".   It makes me want to put a shut off valve in my old Emerald. I wish he had detailed which valve he used.    RonB

Your welcome gentlemen.  I thought he did a good job too.    I have never smoothend out the crush rings either.

Thanks to Ramon for the video referral and to the tech who explained how to service the solenoid I was able to get it out and cleaned.

A before picture showing all the crud. I hope to put it back together tomorrow and cross my fingers it will run.

PS, Onan charging $300 for such a simple carb is outrageous. They beat Apple for being greedy.

Thanks to Ramon for the video referral and to the tech who explained how to service the solenoid I was able to get it out and cleaned.
A before picture showing all the crud. I hope to put it back together tomorrow and cross my fingers it will run.

This makes me consider opening up our 20-year-old Onan's carburetor to clean things out. The generator has never been touched except for oil changes and to check the spark plug and air cleaner.

The fuel cutoff valve is a good idea but folks should still run their generators monthly to keep the armature windings dry and the oil free of moisture.
Run regularly, the carburetor should not gum up from evaporated gasoline.

The fuel cutoff valve is good for those who store their RV over the winter for several months.
Adding a switch to disconnect the fuel solenoid is another way of emptying the float bowl.

Larry

The fuel cutoff valve is good for those who store their RV over the winter for several months.
Adding a switch to disconnect the fuel solenoid is another way of emptying the float bowl.

Ah, use either of the above solutions, then run the generator until the bowl is empty.   Gotcha.

Need to shop for a fuel cutoff valve.

I got it back together. It fired up. I almost did a happy dance. It ran for three minutes and died.
Now it's back to starting, running for a few seconds and dying.
I think my next thing to do will be to attach a bit of C4 to it.
A man must know his limitations.

I got it back together. It fired up. I almost did a happy dance. It ran for three minutes and died.
Now it's back to starting, running for a few seconds and dying.
I think my next thing to do will be to attach a bit of C4 to it.
A man must know his limitations.

Don,
Sounds like more junk it getting into the main jet.  Might want to check it out again.  Is there a filter somewhere on the rubber line that goes further back?  Or maybe the line is deteriorating inside?  Is it still soft? 

This makes me consider opening up our 20-year-old Onan's carburetor to clean things out. The generator has never been touched except for oil changes and to check the spark plug and air cleaner.

Larry, that's a good run for 20 years.  You have taken good care of yours and it shows with this timeline.

Larry, that's a good run for 20 years.  You have taken good care of yours and it shows with this timeline.

With the exception of a rotted fuel line that caused the generator to run for short periods before stalling.
It has been trouble-free with only normal maintenance required including monthly generator runs.

With the additional solar and lithium batteries, the monthly runs have become more important since the generator is not used much anymore while traveling. It is only used when A/C is needed or in a rare situation to charge the coach battery, which has not happened yet.
It is still a good thing to have, power failures do occur at home and it's good to have a way to power the few things that need it, keeping the refrigerator happy is the primary use.

Larry

Hi Don.  Another video from Ritchie showed how to replace the in-line fuel filter. What an awkward place to put that filter!  Seems to me that it might be partially plugged in your application. If it were unable to supply as much gas as the generator wanted, it might run for quite a while, until the load switched on, and increased how much fuel per minute the generator needed to stay on.  RonB

Thanks Ron, I am trying to build up the mental fortitude to replace the fuel pump and filter. I have done it before and it was no picnic.  Getting the control board back in is a real PIA. I will procrastinate until I finally break down and order the parts, over $200. And there is no guarantee it will solve the problem.

It will now run for 2-3 minutes until it fails. I will try to rig a sketchy fuel container hung from over the generator with Sea-foam in it to ensure there is no crud in the carb. I don't see how there would be.   

BTW, I have not put a load on it yet.

It will now run for 2-3 minutes until it fails. I will try to rig a sketchy fuel container hung from over the generator with Sea-foam in it to ensure there is no crud in the carb. I don't see how there would be.   

I was going to suggest this.  Assuming you will unplug power to fuel pump?    Also, have you tried to pump a cup or so out  of the fule line to see if any debris in the catching container? 

I was going to suggest this.  Assuming you will unplug power to fuel pump?    Also, have you tried to pump a cup or so out  of the fule line to see if any debris in the catching container? 

Yes, I will plug the fuel line from the fuel pump. And yes I have pumped out a 1/2 pint from the tank.
The carb bowl is clean. Whatever is above the float I don't know about.

I missed 1 monthly maintenance run and my gen wouldn’t run. This time I bought one of the cheap Chinese knockoffs, which did resolve the problem. Now I close the fuel shutoff valve and run it to fuel exhaustion before inactivity longer than a week. I can buy many of the cheap carbs before equalling the cost of another authentic carb.

I hate to let this thing beat me.

Today's test eliminated the fuel in the gas tank as the culprit.
I connected a fuel line BEFORE the fuel pump/filter to a container of clean gas. It starts and runs for 3-4 minutes surging all the time. By that I mean the butterfly valve on top of the carb goes back and forth like it possessed. 
Then it settles down and runs kinda smooth for a few more seconds until it dies.
The code is 3-3, which is not a code in the micro quiet owners manual.

So I have cleaned the carb bowl and solenoid.

The remaining possibilities are:
Fuel pump/filter
Something with the carb.

I am going to have to bite the bullet and replace fuel pump/filter.
Edit: I am betting I did not buy a genuine Onan fuel pump for $150 when I replace it about 3 years back. Probably bought brand X for $30 not knowing there is supposed to be difference in pressure.

Would you please look at your carb and see if there is screw where the arrow is pointing to.

Question: Do you know the function of the screw just above the arrow pointer?

Here is mine for comparison.

In my carb photo it looks like the carb is not connected on the right. This is an optical illusion - there is a glossy black 1/2” spacer between the carb and the engine block that looks like it’s not there! But it is.

Thanks, they look the same. What I thought could be a missing adjustment screw is just part of the casting

Now what could the adjustment screw adjust?

Don,
Was thinking about this the other day.  That screw might be an idle screw which you should not really have to mess with.

Have you measured how much files comes out if you pump it into a container?   I really think you have a clogged Carb.  maybe after needle and seat or up the main jet chamber .  You would need to take the carb off and spray all ports with carb cleaner and air.  I can't find the 4ky carb cleaning video, where you take it apart.  I am finding Marquis gold one but those have larger carbs but the process of cleaning might be the same.  Or maybe even get a new carb.  I feel you have just a code 3 problem (maybe even code 33, a link below explains more) ) ....  this is for 5500 but probably the same,,,  the fuel part.

How to Fix Fault Code 3 on Onan 5500 Generator? (Error Solved!) (https://www.rvandplaya.com/onan-generator-fault-code-3/)

And an option though yours might be more clogged than this... (soaking even more than 1 time might be key)
https://www.youtube.com/watch?v=wX6Pbh7HEMU

More details about codes and more care...   If all cleaning does not work, carb needs to be replaced and with a good one.
https://www.justanswer.com/small-engine/esnzt-onan-4000-wouldn-t-start-cleaned-carb-start-die.html

Ramon
And online service manual.
https://manuals.heartlandowners.org/manuals/Electrical/Generator/Onan%204000/ONAN-Microlite%204000%20Service%20Manual%20Spec%20K.pdf

Don, I'd bet on the screw your referring to is a throttle stop screw. Is it screwed in tight or does it have adjustment? At any rate, I wouldn't monkey with it unless I could get it back to the correct position.

Jon