Ongoing Onan 2800 Genset Problem

[gksmith]

I am having a very difficult time starting my Onan 2800 genset. It seems to be related to temperatures below 70 degrees. It will start and run fine at first, but only for about 10 seconds. I have to wait at least 30 seconds before trying again, else it will not start at all. After waiting, it will again start, but only for about 5 seconds now. When repeating the process, each attempt runs a little longer, until after about 12 attempts it will finally keep running.

I previously posted about this problem about 18 months ago and replacing the fuel pump was recommended. This was done a year ago last June and a new fuel line and filter was added while the genset was out. We used the camper very little in cooler weather since then, so no problems came forth until this trip. This morning the problem became even more severe, with the genset never running beyond a few seconds, forcing me to give up running it.

Can fuel pumps fail so quickly? Could the fuel pump be replaced with an electric one? Since I think it is temperature related, could it be due to a failing automatic choke? Does it have an automatic choke? Any comments or suggestions? Thanks!

[hbn7hj]

Originally Posted by gksmith

Can fuel pumps fail so quickly? Could the fuel pump be replaced with an electric one? Since I think it is temperature related, could it be due to a failing automatic choke? Does it have an automatic choke? Any comments or suggestions? Thanks!

The short answer is yes. Took me three to get one to last. That does not mean that is your problem. I think you can reach in and activate the choke, which is automatic, to help you troubleshoot. You can remove the fuel line after the fuel pump and see if the electric pump is working.

You can also remove the air filter and choke it with your hand over the inlet to see if you can get it to run. It does sound like a fuel problem. If the pump is good then a fuel passage or two is obstructed in the carb. Just guesses.

[gksmith]

Thanks for you suggestions. I am almost at my wits end, having to remove the genset 3 times in 5 years at over $500 each time. Once to replace the control board (which did resolve a problem), second to only adjust the choke, and thirdly to replace the fuel pump, filter, and fuel line. Since labor is the most expensive component and parts are as relatively inexpensive, I am considering replacing both the carburetor and fuel pump at the next service.
Does this seem reasonable???

[hbn7hj]

Dunno, probably, a replacement carb can be had on Ebay for $30 rather than the Cummins charge pushing $300. It would be a better use of your money to be able to drop it yourself.

Let us know what your situation is (driveway, apartment parking) and let’s figure out how to set you up to do it yourself. It ain’t hard once you figure it out and a whole lot cheaper than $500.

If you were in Phoenix you could do it in my driveway.

Replacing the carb and fuel pump does seem like good advice to self.

Is it running now?

I do value a running, installed, generator. For me the next time it comes out an Onan 2800i is going in. Are you in a posiition to do that?

[booster]

Or you could just bit the even bigger bullet and get a new style Onan fuel injected inverter generator. Smoother, quieter, and hopefully more reliable and actually have all the parts available.

[hbn7hj]

A quick look gets a purchase price of around $3k, in stock, and free shipping. I think someone around here got better than that. It does not appear they are back ordered anymore.

There are install problems to solve like the exhaust system. It is different on the new one and no one has posted about the changes required.

[gksmith]

I have a flat driveway, so that is a plus. But my lack of self confidence towards the job is a big negative. The last two times it was removed (one at Cummins), they commented on how difficult it was to do and both times they called me to make sure I wanted to continue! I believe the unit has to be dropped down.
I have been on the road and the last time I tried to start the genset, the temperature was in the 50s and I gave up trying as the run time would not increase over about 4 seconds. Today the temperature is suppose to get into the mid 70s so I will try again. When I get home, I will see if I can manipulate the choke manually.
I have not compared model numbers, but I think Amazon has carbs for a reasonable price, too. At least nuch less than Cummins $300!
I probably do not want to install a new genset as we are almost ready to make a deposit and make the two year wait for a new Class B, but I sure would like to have a working genset in the meantime!
Thanks!

[RT-NY]

Originally Posted by hbn7hj

The next time it comes out an Onan 2800i is going in.

Just out of curiosity, are the newer Onan 2800's drop-in replacements, like for a 20 year old generator in an old Dodge Roadtrek?

[hbn7hj]

There is a thread on here written by a Canadian fellow detailing the removal and replacement of the underhung generator. The instructions are quite good.

The AC power line goes through the floor to the transfer switch. Most of us end up cutting it and put in a junction box on a frame rail after a removal or two. It isn’t too difficult to pull the wire from the transfer switch.

You don’t need a special lift to drop it and everyone that does it seems to develop their own technique. The 12 volt line goes direct to the battery with no fuse so you start by disconnecting it from the battery. You can do it if you want to bad enough.

I have done it in a friends driveway in a remote mountain town.

[hbn7hj]

Originally Posted by RT-NY

Just out of curiosity, are the newer Onan 2800's drop-in replacements, like for a 20 year old generator in an old Dodge Roadtrek?

No, not quite. If yours is in a compartment you need to check the height difference for fit. The exhaust comes out the side rather than the bottom and the AC line may come from a different corner. No one that has done it has written up their experience but it has been done in the underhung installation.

[themexicandoctor]

This is my 2 cents working with the best generator guy* in Los Angeles but these options are probably similar to where you are in Nebraska.

Paid $800 to have my 04 Roadtrek 2.8 Onan overhauled & a junction box installed (this is a crucial improvement that makes it very easy to drop & install the Generator - at the time Roadtrekdid not come standard with such a box).

Turned out the reason my unit wouldn't run was a little white plastic piece that gets worn away, about a $1.50 part deep in the generator that necessitated dropping the unit

Next.

Then during the pandemic the Regulator went & my Onan expert was closed - cannabilized a Regulator for $50 off another defunct generator in his yard (saved $250+ over OEM new), & had a Lawnmower Shop do the install, $300 or less including Labour.

My suggestion; find a Lawnmower Repair Facility - the Generator is essentially a Lawnmower Engine & these guys work on them all the time at a fraction of the cost of a Specialist.

[rtbill]

If this is in a Chevy Roadtrek have you tried starting the engine first? Pressurizing the fuel tank can help start the generator. Don't know if this helps on Dodges.

Have you tried ether? (Starting fluid.) The Onan in our '01 Roadtrek will never start when not used after 3 or 4 days, even with the engine trick. A good squirt of starting fluid gives the generator a kick in the pants, so to say. It may stall immediately, but after a second squirt it coughs to life, runs rough for a few seconds, and then settles down and runs fine. It will start right up the next day.

For sure something is wrong with our generator, but given the expense of having an Onan dealer work on it, and the fix not enduring long, I don't mind buying one or two cans of ether every year.

[ChicagoTom]

Often times when it starts and dies it can be low oil. Even a few ounces. Oil gets pumped up, and then causes the low oil safety to kick on and turns off the generator. Also, if you are in a different location make sure the simple adjustable altitude is set correctly. Sometimes we look for the difficult solutions and it may be something as simple as that.

[Alec]

For what it's worth
I bought a new Paseo in 2018 with an Onan. The Paseo sits most of the time. When I tried the generator after sitting for probably a year, it would start and immediatly shut off. Same thing as I tried various times over the next few weeks. Attempted to get an Onan rep to come look at it, but living nearly 100 miles from their rep's location, never worked out.

Since the unit was still under warranty, with about 1.8 hours on it, I called an Onan service center and made an appointment. Got to the Center only to discover their only qualified person was out, and no one could look at it. Asked me if I could leave it for a few days. No, since i lived 100 os so miles away and hadn't arranged for a ride home.

Preparing to head home, and a bit annoyed, one of the service folks asked if I had tried SeaFoam? No, never heard of it. He said to try it. Okay, went home aand looked it up on Amazon, read the reviews, and ordered a case of it, along with a spray can of the stuff.

Poured a can into the gas tank and let it sit for a day or two. After sitting for a day or two I gave the Onan's carborator a good shot from the spray can, noticing as I did the choke flapper might have acted a bit sticky.
Tried starting the generator two or three times in quick succession and the little bugger started and kept running! Now I try to remember to start it every two or three months and it never fails to start. I do add a can to the gas tank whenever I fill up.

Maybe the choke was stuck, or this SeaFoaam stuff is that good, but my Onan starting problem went away, so that's my story and I'm sticking with it.

One thing I notice after running it few minutes, the generator starts to "lope", running fast then slow, fast the slow. I can't remember if that "lopeing" stops if I add a load, like the a/c, but I assume that adjusting the idle setting may eliminate that.
Alec

[themexicandoctor]

I recently had a glorious Seafoam experience myself with an Italian Scooter & its carb - there is a reason Mechanic's call it a "Tune Up in a Bottle..."

My suggestion to the poster above, run your Generator at least 2 hours per month, or one hour every 2 weeks, after it has started for 5 minutes, put it under load ie; run the AC/heat Pump for the duration.

[Alec]

Read my missive below. I had the exact problem. I think that perhaps the choke was stuck, but haven't had a problem since using that SeaFoam stuff.

[patgearty]

I knew this day would come! My Onan 2800 will not start. LP fueled. Only 260 hours and well maintained, exercised. Exercised it last week and it ran Ok for 1 hour. Shut it down and now it cranks but will not start. No indication of it firing up. I will do some basic trouble shooting but am preparing for it being beyond my repair ability. Given the service challenges many have experienced I am considering replacing it with the new 2800i. Do you have recommendations for fair and quality Onan shops in the Twin Cities that would service or replace my geny?

[Rlum]

Originally Posted by patgearty

I new this day would come! My Onan 2800 will not start. LP fueled. Only 260 hours and well maintained, exercised. Exercised it last week and it ran Ok for 1 hour. Shut it down and now it cranks but will not start. No indication of it firing up. I will do some basic trouble shooting but am preparing for it being beyond my repair ability. Given the service challenges many have experienced I am considering replacing it with the new 2800i. Do you have recommendations for fair and quality Onan shops in the Twin Cities that would service or replace my geny?

Generally LP generators fail to run because of low propane pressure. I have had a portable unit have the same issue. The pressure needs to high enough so the LP can ignite. Make sure your regulator is working properly pressure wise. As for the 2800i, I just installed last October. Been only out a 2-3 times since installing it. I really like it so far. Much quieter than original gas model.
Uses very little gas too. If your LP unit repair costs are over 1K. I would look at replacing it with a 2800i. They are not cheap but easier to maintain.

[patgearty]

Thanks Rulm. I assume my motorhome LP pressure is good. Stove burners, furnace and fridge all are working normal on LP. It appears there is a LP regulator in the generator, and I will see if its accessible when I get under the rig. Nice to hear you did the 2800i. DIY or a service provider? Any guidance on that project would be appreciated.

[Rlum]

Originally Posted by patgearty

Thanks Rulm. I assume my motorhome LP pressure is good. Stove burners, furnace and fridge all are working normal on LP. It appears there is a LP regulator in the generator, and I will see if its accessible when I get under the rig. Nice to hear you did the 2800i. DIY or a service provider? Any guidance on that project would be appreciated.

I had a local authorized guy install it. He is a very, very small shop. Works by himself. Actually installation is not difficult after watching him. He allowed me to connect wires to the junction box. He used a forklift to remove old unit and install new one. You can install yourself if you have a jack to remove and install the unit. Just some drive up ramps to get under the vehicle is enough.

A gas genny produces a bit more energy than LP. LP exhaust is not as smelly as gas exhaust. The 2800i idles very low and is fuel injected. It has some anti vibration feet built into it. Inside the van when genny is running, one can barely feel the vibration and hear it. The genny only ramps up when there is a load on it. When I charge my batteries, I cannot hear it ramp up its rpms. So far it has been working fine.