Onan generator puzzle

[felixkagi]

Here we go again, just a few month past a five day shop experience the Cummins Onan 2.5 HGJBB-1125A LP generator again will not start. Give it a shot of starting fluid and she will purr right up and run, even under a good load. Shut off after an hour or so and she won't kick on without starting aid.

Any ideas? Similar experiences?

Just as a side note; a Honda EU2000 with a GenConnectX propane conversion sounds more and more tempting. I understand one of these will run the AC with an aftermarket soft-start installed. No more noise and vibration inside, quiet and trouble free. Perhaps not quite as convenient, but what is convenience if it does not work.

[GMFL]

It's a fuel problem. Is the generator propane only. If so problem could be in the regulator pressure being to low to allow for a clean start. Starter fluid is getting it up and going and then it is fine?

[felixkagi]

Originally Posted by GMFL

It's a fuel problem. Is the generator propane only. If so problem could be in the regulator pressure being to low to allow for a clean start. Starter fluid is getting it up and going and then it is fine?

Regulator pressure on the main tank?

Yes it runs just fine once I get it started with s fluid.

[Ryoungca]

Not sure I can contribute to the diagnosis, I do have a question, how do you administer the starting fluid? Crawl underneath?

On the diagnosis, I heard from my Onan service company that Onan is tightening up the requirements to be a sales and service dealer. Your shop should stand by their work even a few months later.

[Titus]

I never would have thought to give a shot of starting fluid to an LPG engine. And like Ryoungca am wondering where you would do so. Drop the spare tire, remove the rear cover of the Onan, and then (try to ) find the air filter?

The low pressure regulator has a vent tube that sticks out the bottom of the generator pan. My vent tube is covered by piece of foam 'filter'. But if yours isn't then it could be plugged. I think this would prevent both starting and running, but it is the easiest place to start. Then I would check the high pressure regulator on the LPG tank - unlikely but relatively easy to do. Then change the spark plug (again unlikely, but easy. Problem sounds like fuel, not spark or air.) Then check the low pressure regulator on the generator. I don't know if it is adjustable, or if you simply replace it. Carbuerators have starting (choke) fuel, idle jet, and a venturi that sucks more fuel as load increases. I don't know how the low pressure regulator handles starting/idle/load transition, but that seems to be at the heart of your problem.

[Titus]

When all else fails, read the manual. After posting the above I looked on-line. See this link for troubleshooting. My suggestions above appear reasonable. Lots of good info in here (starting page 8-22) on the primary pressure (11 " H20) and the secondary (demand)regulators.

http://b190.com/files/Onan-Cummins%2...e%20manual.pdf

[Protagonist]

Originally Posted by felixkagi

Give it a shot of starting fluid and she will purr right up and run, even under a good load. Shut off after an hour or so and she won't kick on without starting aid.

Under the troubleshooting philosophy of "check the easy things first"— are all 120vAC loads switched off when you try to start the generator? Trying to start under a load could cause the symptoms you describe. And it's both easy and important to verify that all loads are switched OFF before trying to start the generator. Then let the generator run for about 20 seconds before you start adding loads. No matter if it's an Onan 2.5k propane-fueled generator, a Honda Eu2000i gasoline-fueled generator, or a big 100kw Generac SD100 diesel-fueled generator. Conventional wisdom is to never start it under a load.

And in your post you DID say "even under a good load" so from your own admission I'm tempted to chalk this problem up to user error. But further experimentation is required in order to verify the diagnosis.

Try starting the generator again NOT under a load as recommended in every generator user manual I've ever seen, and please let us know what happens. If it starts, then user error was the culprit. If not, then we can explore other possible causes.

[Titus]

I don't believe the electrical load when starting matters as the generator will not accept load until a period of time has elapsed. On mine it takes about 2 minutes before the generator lights up the EMS. You can have all the load 'downstream' of the EMS that you want, but generator power does not reach that load until the generator is up and running.

[Protagonist]

Originally Posted by Titus

I don't believe the electrical load when starting matters as the generator will not accept load until a period of time has elapsed. On mine it takes about 2 minutes before the generator lights up the EMS. You can have all the load 'downstream' of the EMS that you want, but generator power does not reach that load until the generator is up and running.

Perhaps. Even probably. Almost definitely.

But my suggestion is easy to check, and even if it doesn't solve the problem then no harm has been done to try a "no load" start by manually switching off the loads rather than relying on the EMS to hide the loads until the generator is ready to accept them. All it costs is a few minutes' time— and no particular effort— to try it and see. After all, the problem may actually be the EMS. We don't know.

I used to be an engineer before I retired, and engineers have a reputation for seeking complex solutions to complex problems. Now that I'm retired, I'm trying to make sure we don't also apply complex solutions to potentially simple problems. So it only makes sense to propose a simple solution first, before proceeding to more complex ones if the simple ones don't work.

It's also important to offer the OP as many alternatives as possible. I'm not trying to downplay your experience or your advice to the OP. But I'm sure you would agree that one should try all of the alternatives that don't require crawling under the van before proceeding to the alternatives that do require it.

[Titus]

Felixkagi,
Am I reading your OP correct that the Onan will start on LPG (rather than starting fluid) for a short period of time after it has been shut off, but not after a longer (>1 hour) period of shut-off? This could be a significant clue, though I am not sure what that clue means.

There is not a choke on an LPG engine, but I see from the manual that older gen sets have a 'built-in automatic priming solenoid' (see pg 8-23, 24 of the link). That may not be working correctly, but is only noticeable when the engine is cold.

[Tronadora]

I had this same problem. We were getting propane to the furnace and cooktop but the generator would not start. The dealer measured my gas pressure getting to the generator as being about 25% of normal. They replaced a regulator and that fixed it. Evidently the feed to the interior appliances branches off before this regulator that feeds the generator.

Mark

[felixkagi]

Originally Posted by Ryoungca

Not sure I can contribute to the diagnosis, I do have a question, how do you administer the starting fluid? Crawl underneath?

On the diagnosis, I heard from my Onan service company that Onan is tightening up the requirements to be a sales and service dealer. Your shop should stand by their work even a few months later.

I have two ramps and a creeper to get under the car, remove the little cover, press the start switch that is right there a spray a little starting fluid into the air filter hosing. Quit simple though obviously I can't (won't) crawl under the rev overtime I run the generator.

The (Cummins) dealer that fixed it the last time? Well, that was on a trip and that shop is 1,200 miles away.

[felixkagi]

Originally Posted by Titus

I don't believe the electrical load when starting matters as the generator will not accept load until a period of time has elapsed. On mine it takes about 2 minutes before the generator lights up the EMS. You can have all the load 'downstream' of the EMS that you want, but generator power does not reach that load until the generator is up and running.

That is correct; the generator does not start under load, it takes a few minutes before potential loads kick in.

The breather tube is free otherwise it would not keep running (with starting aid)

The priming solenoid works and gas flows through the line (removed the hose to check) so it could be something forward from there, the regulator or the fuel mixer?

[felixkagi]

Originally Posted by Titus

Felixkagi,
Am I reading your OP correct that the Onan will start on LPG (rather than starting fluid) for a short period of time after it has been shut off, but not after a longer (>1 hour) period of shut-off? This could be a significant clue, though I am not sure what that clue means.

There is not a choke on an LPG engine, but I see from the manual that older gen sets have a 'built-in automatic priming solenoid' (see pg 8-23, 24 of the link). That may not be working correctly, but is only noticeable when the engine is cold.

My description may not have been clear. NO the generator will not re-start on its own even after an hour of running. As I mentioned the priming solenoid works and lets fuel pass, since this is located on the outside of the generator I can check it.

[felixkagi]

Originally Posted by Tronadora

I had this same problem. We were getting propane to the furnace and cooktop but the generator would not start. The dealer measured my gas pressure getting to the generator as being about 25% of normal. They replaced a regulator and that fixed it. Evidently the feed to the interior appliances branches off before this regulator that feeds the generator.

Mark

............huh? Sounds like a good possibility. That regulator is inside the generator itself.

This would require a takedown of the generator and proper tools to analyze propane delivery, something a little beyond my capabilities.

Before making an appointment and the ardent trip to a Cummins Onan Service Center, I will take the handle end of a hammer and tap the regulator, which is right inside the door. As Protagonist suggests, I also will turn off the main breaker on the machine to make sure that absolutely no load is present when starting.

We'll keep you posted

[felixkagi]

……puzzle continues

Well, if you have a generator issue on an AI there aren’t many places to go to other than a Cummins-Onan service center, for me that’s a one hour drive. Just about anything except an oil change, cannot be done without taking the generator down from its mounted position and out onto a work bench, that with a coffe- and/or a lunch-break will take some time. Then it’s likely they won’t have the part, so you will be sent home with “we’ll give you a call”.

When the call came towards evening; “we need to order a fuel mixer, should be here in two days, we’ll let you know”.

A fuel mixer? Huh, wasn’t it just some five and a half month ago when a Cummins service center in Louisville KY during a road trip some 1,200 mile from home told me the same thing. They held me up for 7 days, waiting at the shop every day for four and more hours, telling me “it should be on the parts truck tomorrow”.

Finally they had it running, told me it’s under warranty, which it should have been with just little time left on the 2 years. Asking whether I need to sign any papers, they said “No, you are good to go” I thought that was a little strange with a large outfit like Cummins.

Yes, the generator did run, but it was hard starting and seemed to run a bit rough. Now here we are, same issue, same part not working. Did they really install a new part? Will Cummins stand behind this? No paper work.

Frankly, if I purchased a new AI today or for that matter any Class B, I'd skip the built in generator altogether, invest the money in a decent solar system instead, get a high powered alternator and purchase a Honda 2000EU or similar for the cloudy days and you are good to go with a whole lot less headaches.

It is not so much the money, though any service on these generators will be expensive, it is the inconvenience and time one will have to spend.

I am certain that this Onan generator will work just fine once I get it back, but for how long?

[FlyFishinRVr]

Originally Posted by felixkagi

Frankly, if I purchased a new AI today or for that matter any Class B, I'd skip the built in generator altogether, invest the money in a decent solar system instead, get a high powered alternator and purchase a Honda 2000EU or similar for the cloudy days and you are good to go with a whole lot less headaches.

Exactly why I keep going back to the Advanced RV site. They don't install generators for the very reason you state (unless a customer insists.....they are custom builders after all), and now with their partnership with Volta, they seem to have a very good, albeit expensive, solution to the whole generator conundrum. All I need now is that winning lotto ticket and I'm there....

[wachuko]

Originally Posted by FlyFishinRVr

Exactly why I keep going back to the Advanced RV site. They don't install generators for the very reason you state (unless a customer insists.....they are custom builders after all), and now with their partnership with Volta, they seem to have a very good, albeit expensive, solution to the whole generator conundrum. All I need now is that winning lotto ticket and I'm there....

Expensive is an understatement

[felixkagi]

It has been about 9 weeks since the 2013 AS went to a Cummins-Onan service center and was diagnosed as needing a new fuel mixer.

Oh, not again; thats what they told me back in spring in Louisivlle KY where they supposedly installed a new fuel mixer and sent me on my way after 6 days of sitting at the service center. They told me it was all under warranty and come to think, I never received any paperwork.

So I got the call, the generator with a new fuel mixer is ready to be installed. Punctually at 8AM today I was there. 7 weeks it took to get a fuel mixer. None to be found on Onan shelves, it came from the Subary factory, wherever that is, the maker of the engine I was told.

After patiently waiting for over 4 hours, I was on my way, again no paperwork. Warranty and they will email me something. Had to run some errands while in town and out of curiosity I went to the rear to see and hear how the thing was running. Five try's on the start button, no luck so I drove straight back to the shop. After another hour and a half the service manager handed me the key back, said it was OK now, with another full year under warranty and I could come back anytime if it does not work.

Well, I drove the one hour back to my barn and guess what, ............ it still doe not work. Yep, they took my call back at the Onan shop and told me Jim the service manager would call me back. He hasn't.

Warranty is great, but if something does not work, what good is it.

This little generator is sufficiently complex that it takes knowledge and experience to get things working. I conclude that there is a bit of lack thereof but then could it be that I just got a lemon?

Contemplating the next step I guess.

[Boxster1971]

Originally Posted by felixkagi

It has been about 9 weeks since the 2013 AS went to a Cummins-Onan service center and was diagnosed as needing a new fuel mixer.

... None to be found on Onan shelves, it came from the Subary factory, wherever that is, the maker of the engine I was told.

... Warranty is great, but if something does not work, what good is it.

This little generator is sufficiently complex that it takes knowledge and experience to get things working. I conclude that there is a bit of lack thereof but then could it be that I just got a lemon?

Contemplating the next step I guess.

The small LP engine in these Onan generators is made by Subaru.

http://www.subarupower.com/

Good luck - this has to be frustrating.