Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

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Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

May 02, 2022, 11:44:59 pm

Having gone through 25 pages of technical subjects about the above subject, I could not find any references. Neither could I find any on the Companion. If I missed something" "My apology".
Since this unit has been mounted below the floor, there is very little access. Has anyone gone through this process? Are there any special wrenches or "tricks" to undo the bolts?
My intent is to replace the entire fuel system, including the carburetor, to the tank.

Aad Rommelse

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #1 – May 03, 2022, 02:54:47 am

Hi Aad; Long time no see; The problems you are having with your genset are likely not the carb or fuel pump. You did't say how many hours you have run it, but with a 2001, it may be the same as my 1999 Emerald II (BGE). The few inches of hose that goes to the generator isn't inside the tank, but was installed by Lazy Daze at the top of your tank, and goes to the generator fuel pump. You were having this problem a year ago, and filling the tank up 'fixed' the problem, but really it didn't. With a higher fuel level inside the tank, the generator pump doesn't have to suck as hard on the deteriorated section of rubber hose at the top of the fuel tank. So it doesn't suck as much air, and will run ok, until the level of gas in the main tank is lower, and the generator pump can't get enough gas to run normally.
Before you spend a lot of time throwing money at the generator, try this test. Get a section of rubber gas line and attach it at the generator fuel pump inlet. Put the other hose end in a gas can (they are mostly plastic anymore) and see if the genset runs normally out of the gas can. If it does, but doesn't run consistently from the motorhome tank at medium to 1/2 tank of gas, then likely it is that 4" hose section outside the tank at the top.
The only cure is to drop the tank far enough for someone to put in new hose. This isn't in the tank, but near the top where the fuel pump, tank level sensor, and feed tube for the generator are attached. RonB

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #2 – May 03, 2022, 10:35:11 am

"The only cure is to drop the tank..."

Been there, done that! And before everything got buttoned up the old plastic fuel line from tank to generator got replaced with Stainless. Just a bit of insurance!

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #3 – July 31, 2022, 06:46:51 pm

Yes, Ron, you are correct. I must be the flexible section of hose on top of the tank that is the culprit. I disconnected the supply line at the generator, put a short hose in a gas can ad it started right up. As a result of unforeseen circumstances, that where I left it.
Finally, I have some time to take care of this matter. When you did yours, how far did you have to drop the tank to reach the connection?
Beyond the end of the strap bolts? Or is there enough room between the floor and the top of the tank to change the hose?

I actually already turned our ownership over to our daughter and her family. However, there lifestyle has become so busy that our Lazy Daze has come back to us again. Shortly you will see her posted.

Aad

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #4 – July 31, 2022, 07:07:10 pm

Quote from: Aad Rommelse - July 31, 2022, 06:46:51 pm

Finally, I have some time to take care of this matter. When you did yours, how far did you have to drop the tank to reach the connection?
Beyond the end of the strap bolts? Or is there enough room between the floor and the top of the tank to change the hose?

Larry Wade was able to replace the cracked section of fuel hose without dropping the entire tank. He used threaded rods to drop one side of the tank, and then reached into the tights space to do the repair by feel.

Fuel tank generator hose replacement | Flickr

He later had to drop the whole tank for fuel pump replacement.

I replaced the rotten section on my rig while replacing the fuel pump. My advice, if you haven't done the fuel pump already, would be to drop the tank and do them both at the same time.

Here is my account of dropping the tank. If you look upthread, you can find discussion of the threaded rod method and other various advice. Fuel Pump Replacement and Dropping Fuel Tank

Rich

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #5 – July 31, 2022, 10:13:24 pm

Thanks, Rich, for the reference to Larry's post about the short section of generator hose replacement. I have seen quite a few of Larry's pictures in general, but not this particular one. about the threaded rods. I had my fuel pump replaced not too long ago, so I do not anticipate dropping the tank completely.
From Larry's pictures I noticed that He did not drop the tank too much on the driver side. Do you think that just loosening the bolts on the driver side and backing of to the threaded rods on the passenger side of the tank will create enough clearance to reach the generator fuel outlet on the tank? Just curious.
Yes, even if family circumstances prevent me from traveling, I still do not mind crawling underneath the Lazy Daze.
Looking forward to a response.

Aad

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #6 – August 01, 2022, 01:59:17 am

Hi Aad; I'm sorry that you couldn't find a family member to keep your cherished LD 'close to you', But someone here will take care of it and hopefully appreciate the good care you've given it these many years.
I haven't replaced my hose yet, and I haven't had any issues running my genset yet.... But standing by for that possibility. RonB

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #7 – August 01, 2022, 04:49:13 pm

Yes, you have the dreaded rotted fuel hose problem that all LDs of our vintage have.
I don't know about MBs but our 23.5 FL generator fuel line could be replaced by partially dropping the tank, and hanging it on long pieces of all thread. It also requires long arms and hands used to work when they cannot be seen.

I agree that at the age of your rig, dropping the tank and replacing the fuel pump and the emission hoses, along with the generator's fuel line, is advisable.

Larry

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #8 – August 01, 2022, 10:36:55 pm

Thanks, Larry, for your input. This more than likely will be my last project to our toy. Although I passed the title already on to our daughter and son-in-law, their schedules are such that there would not be used for this Lazy Daze for the time being.
Unfortunately, Mary's health has reached a stage where it is no longer safe for us to travel together. However, we have enjoyed 103,500 enjoyable miles with our Lazy Daze.
With regard to your advice about replacing the fuel pump, this we had to have done during one of our road trips about 6 years ago.
I assume that all required equipment on top of the tank was replaced at that time too.
With regard to dropping the tank to replace the generator hose connection, did you just lower the driver side on your picture only with the treaded rods (Bolts). Or did you lower the treaded rods, connected to the holding straps on the passenger side and lowered the tank evenly on both sides. Just curious.
Larry, though this side I have enjoyed learning a lot by trial and tribulations from many people, but particularly from you. My sincere thanks. Our Lazy Daze may be gone soon but the memories will remain.

Aad

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #9 – August 02, 2022, 01:27:46 pm

Quote from: Aad Rommelse - August 01, 2022, 10:36:55 pm

With regard to dropping the tank to replace the generator hose connection, did you just lower the driver side on your picture only with the treaded rods (Bolts). Or did you lower the threaded rods, connected to the holding straps on the passenger side and lowered the tank evenly on both sides? Just curious.

Threaded rods on both sides of the tank straps allow the tank to be lowered as far as the lines permit. You will still need long arms to reach the hose clamp that secures the generator's fuel line to the outlet.
Not sure how well this will work on a Mid Bath or if it will provide adequate access..

Larry

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #10 – August 02, 2022, 03:10:17 pm

Hi Aad,

Do you know if your fuel tank has a drain plug? Our 2002 did and when I replaced the fuel pump and generator fuel line many years back draining the fuel made the tank much easier to handle. My memory of that project is getting dim, but since we had Bigfoot jacks then, I likely used blocks under the jack pads (with front wheels chocked) to lift the rear high enough to put heavy duty jack stands in place and then lower the rear onto the jack stands. I am pretty sure I used a floor jack with some blocks raised to support the bottom of the tank and then removed the mounting bolts and then carefully lowered the tank enough to access and disconnect the electrical and fuel lines. Then the tank could be fully lowered and moved to where it was easier to replace the fuel pump. Installation would have been the reverse.

Hope this helps,
Art

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #11 – August 04, 2022, 11:41:43 am

Carb cannot be removed without genset removal, and even with the genset out the carb bolts are immensely difficult to access.

Carb bowl can be removed and the needle cleaned without removing anything, I highly recommend checking the fuel lines, on mine the fuel pump made a loud ticking noise when it was sucking air through a cracked hose.

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #12 – August 15, 2022, 09:10:59 am

I have a 1988 MB with Emerald.
I have long arms.
I have changed the fuel tanks generator hose without dropping the tank. Frustrating but done.
I ran the generator with 2' piece of hose from a gasoline can.
I have changed the Carburetor with out dropping the generator. The 1988 emerald Carb is in the open. Combination wrenches, a nut driver, Needle nose pliers, Multimeter with Frequency, two 1200 watt electric plug in heaters. and utility knife were the tools.
Nut driver or 1/4" socket set to remove the air cleaner.
Remove the governor link clip and link. disconnect the fuel line.
Combination wrenches to remove Carb.
Reverse to install. Make sure the Air cleaner screws do NOT touch the Choke shaft. I had to shorten one screw.
Plug in one extension cord into microwave plug and extend to the generator, connect Frequency meter and one heater. connect one heater to other plugs.
Warm up generator, set to a stable run.
Then turn on the heaters to finish Warm up.
then set up Carb and governor per instructions 62 Hz, 57 Hz. idle stop at 54Hz etc.

the Aftermarket governor rod hole was oversize. Plastic tubing made nice spacers.

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #13 – August 15, 2022, 06:45:05 pm

We rarely use our generator but about a year ago when in camp I decided to exercise it. It cranked but would not run. Though our LD itself ran fine, at about 150K miles it was overdue for a fuel pump change. And of course I'd heard many stories about deterioration of the hose connecting the fuel tank to the generator fuel line. So I decided to have all this addressed at the same time and had our mechanics change the fuel pump, the fuel line connections and then check the generator for proper operation.

Once all that was done the generator still wasn't running, so they did a quick cleaning of the carb (spraying carb cleaner in the air intake is my guess). The generator started working. But over the next few operations of the generator it was clear it wasn't running well, with a lot of surging.

So today I took it back in, fully expecting them to say it needed a new carburetor, since the ones on our vintage of motorhome are MOL sealed and supposedly not serviceable. I was surprised when they called a few hours later and said the LD was ready for pickup. This time they had removed the carb, "dismantled" it to some degree and cleaned it and reported that the main jet was clogged, but no longer. I asked about the supposed sealed nature of the carb preventing its service and they said you simply need to know how to disassemble and clean it. When I got the LD home I fired up the generator and it ran like it did when new.

I find it hard to imagine that someone would have replaced your fuel pump without installing a new hose connection on the generator fuel line. But the gas can test reported by others would tell you if that's the problem. If it runs fine from the can then it's likely the fuel line that is the problem. If it runs poorly or not at all from the can then the problem is with the generator.

Before I went to the expense of changing all those likely very pricey Onan fuel system parts I'd try to find someone who can properly clean and adjust the carburetor. Based on my experience you might find someone who can do that properly and get the generator working for less than the cost of the parts you were planning to replace. If after that they say you need those parts you could proceed to replace them yourself if that's your preference.

In the end I'm not convinced we had a fuel line problem. I think after almost 20 years the carb was dirty and clogged and I was glad to find someone who could clean it rather than replace it. Of course it could have had a fuel line problem too. And it's possible debris from a deteriorated fuel line got into the carb. Who knows? But in the future I'm going to make generator carb cleaning part of servicing the motorhome if the generator isn't running smoothly.

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #14 – September 18, 2022, 01:09:29 am

Life of an amateur mechanic.

Remember my generator problem and all the well-meant suggestions and referrals to the short hose on top of our 2001 Midbath?
As I mentioned before it was not the generator after I followed advice and tried it from a gas can next to the generator. It worked. You all had me convinced that it was the short hose on top of the tank. I tried Larry's way to slightly lower the tank. My butchered hands and arms told me to me to forget it and dropped the tank completely to the floor and ruining the fuel supply and vent hoses. Typical amateur work of course. After thorough inspection all hoses, including the short one for the generator, were in excellent shape.
Note.: A few years ago, I had my fuel pump replaced and at that time they must have replaced all hoses, judging by the quality.
After reinstalling the tank, replacing the fuel supply and vent hoses, back to the generator. for further inspection of a line problem.
Low and behold, this did not take too long. After removing the flexible hose, connecting from the plastic supply line to the generator, the problem was evident. The protective cover was damaged from rubbing against something and the fuel hose had a crack in it.
End result!!! After replacing the hose, the generator runs as a dream again.
Hopefully, others can learn from my amateur skills. Looking back at it, to me it was a fun project and, as a result of my age and family circumstances, the last mechanical project of my life.
From the time that I joint this group, I have learned a lot, sometimes being stubborn, but most of the time with enjoyment. Thanks to all, who have guided me over the years.
Hopefully, I can use the skills that I learned, in my afterlife and I shall credit this group for it.

Aad Rommelse.
Aad Rommelse

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #15 – September 18, 2022, 12:02:39 pm

"After removing the flexible hose, connecting from the plastic supply line to the generator,..."

As an added bit of insurance I replaced that plastic supply line with stainless steel!

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #16 – September 30, 2022, 03:30:56 am

I just bought a 2003 MB that has a faulty generator. It try’s to start but doesn’t.
Is the thread here about replacing the short fuel line limited to any year model or year is it for all LD’s?

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #17 – September 30, 2022, 11:22:22 am

Hi BonesD; (We would prefer a real name); Your year is suspect for the cracked hose issue, but there are ways to check on fuel delivery from your tank, and to check on other parts of the generator before getting into 'dropping the tank' as a first step. How many miles does your vehicle have? How many hours on your generator meter? What model of generator do you have. The Onan Emerald Plus is a way different beastie from the MicroQuiet. Carburetor cleaners often help a lot. And of course the main fuel tank needs to be above about a 1/4 tank for the pickup tube for the generator. RonB

(edit: Many people put their preferred name in their 'profile' line that appears at the lower left under comments.)

Re: Onan 4000 Emerald Plus Carburetor replacement for a 2001 Mid bath.

Reply #18 – September 30, 2022, 12:32:15 pm

Quote from: BonesD - September 30, 2022, 03:30:56 am

I just bought a 2003 MB that has a faulty generator. It tries to start but doesn’t.
Is the thread here about replacing the short fuel line limited to any year model or year is it for all LD’s?

Your new to you 2003 is the right vintage to have rotten generator fuel lines, all LDs built in the early 2000s had or still suffer from this issue.
LD must have had a large roll of very old fuel line, our 2003's LD's fuel line started leaking within a few years.

You will find a short piece of rubber fuel line right at the generator and another short piece up on top of the fuel tank.
The bottom line is easy to change, the top line needs the fuel tank lowered a few inches or totally removed.
Some floorplans allow the tank to be lowered a few inches, using threaded rods, to reach the generator's upper fuel line, others floorplans require complete removal of the tank.
Either way, the rubber lines must be replaced if you wish the generator to run.
If removing the tank, change the fuel pump if still original, along with the fuel tank's emission lines

Fuel tank generator hose replacement | Flickr

Fuel pump replacement | Flickr

Larry

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