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Onan REALLY Noisy - Is This Common?

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Hey everyone. My first post.

Bought a near-new (25K mi) 99 Thor Hurricane 30ftr last fall, here in Alaska.

Never owned an RV with an on-board gen before. Its an Onan, which seems to be the go-to brand.

Looks like (looking at manual, not actual unit, which is in storage) a BGE Emerald 4K

It has about 60 hrs on it, and looks like new (it is the original unit for 1999). I changed the oil and filters and it starts right up and runs "fine".

Have run it for several hours at various intervals, with and without loads (AC), per manual.

So. About "fine". It is VERY noisy, and the whole RV shakes/vibrates while it is running! This CAN'T be right. Can it? Were these things this bad in the late 90s?

I mean, I would not DARE run this in an RV Park. We would be tarred-and-feathered.

Having our RV shop check it out, and there is an Onan/Cummings service center in Town. But I need some sort of baseline idea of how these should actually be working.

Thanks in advance!

Stu - Alaska

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Welcome to the forum. The gas units are fairly noisy. Like DD said check the exhaust system for leaks. Onan may have a upgrade muffler you could try. The outher thing to check is the rubber mounting brackets as they are probbabley hard with age and transmitting more vibration to your coach.

Let us know what you find out.

Bill 

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Thank you Gents.

I am having my service center take a Listen. I wonder if I need to chase down replacement shock/iso mounts thru them or with Onan or with THOR?

Considering having a portable 2K (honda, etc) with us so we can more painlessly (!) run kitchen stuff and peripherals in the Boonies.

Stu

Alaska

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The Honda 2000i portable generator is a good choice to have with you.  It is quiet and light (34 lbs).

As stated above maybe a new muffler and mounting grommets will cure the vibration and extra noise

you are having with the 1999 unit.

Phil Saran

Colorado

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I had the BGE Emerald 4000 on my first motor home (a 27ft Georgie Boy).  Mine was very noisy.  The muffler was old and rusty, so I replaced it.  Didn't help.  I put my hand over the end of the muffler tailpipe and I found that the connection between the exhaust manifold pipe and the exhaust pipe that connects to the muffler had come loose.  You have to take the muffler off to get to the flange bolts.  I did this, tightened them, but in due time they came loose and the bolts and gasket fell out.  I bought a new gasket and hardened bolts with jamb nuts.  Fixed the problem, never came loose again.  To see this part, go to Cummins Onan and look at the exploded view in the parts manual.

 

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Yes, the Onan gas generators are all constant speed and therefore constant noise due to their design. 

I had the chance to blast them at the Chandler FMCA rally and made full use of the opportunity!  I walked up to their tent area and asked why Onan didn't offer an "inverter" style generator and bring their technology up to current standards.  The fellow in the booth thanked me for the comment and asked if I'd consent to recording those comments for a video he was making to take back to the factory for the design engineers - my answer was YES!  For the next 5 minutes I talked about how they were using old technology and the need for updating their product line if they want to maintain their place as the choice for generators for RVs.  The main upgrade needed is for them to get away from constant speed technology and switch to inverter technology.  The other point I made was telling them it's time to do away with carburetors in favor of fuel injection.

Inverter technology allows the engine to adapt it's speed to the load on the alternator while the archaic constant speed technology requires the alternator (and therefore the directly connected engine) to turn at a constant RPM to produce 60 cycle current.  The inverters use electronics to do that job.  

Fuel injection should be a requirement for the 5500 watt "Marque" models and above at an absolute minimum. 

Other manufacturers have been using these technologies for many years now and I find it unbelievable that Onan hasn't embraced these features.

Instead of running that noisy 4000 watt Onan at Chandler, I used a 2200 watt Ryobi inverter generator I purchased through Home Depot for $429.  It compares very favorably with the higher cost Honda in noise and power produced.  It spent most it's time idling and only used 3 gallons of gas during our 6 day stay (we came in on Sunday) at the rally.  My neighbors all had diesel pushers and had their diesel generator exhaust trained at me trying to gas me out and it worked great for them.  If I had used my Onan, I would have used my Camco Exhaust Stack with it but no of those smelly diesels every use them.  I'm a strong proponent of a "stacks only" area at the rallies.  My asthma and that diesel generator exhaust is going to force me away from attending FMCA events.     

BTY:  The Ryobi generator is available through HomeDepot.com for $599  http://www.homedepot.com/p/Ryobi-2-200-Watt-Green-Gasoline-Powered-Digital-Inverter-Generator-RYI2200/203617901   The one I bought has a grey case.  I guess it was older stock and they clearanced it out at the $429 price.  They can be paralleled just like the Honda.

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Thank you for your Stories and advice everyone!

Have used Honda gennies a lot for location AC in our business and made (HA!) the assumption that, well, ALL gens should act like that. The Onan was (literally) a big Wake Up.

Onan dealer here wants $260 just to start a diagnosis (and perhaps apply to further repair?) so I guess I may have to bite the bullet to see if we can at least mitigate this somewhat.

Who knew?
:)

Stu

Alaska

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I have a Honda 2000i .  It is really quiet. When you are inside you can't hear it run. Used it with a travel trailer while dry camping. We were right  on the shore of Lake San Cristobal in Colorado after the host had departed ( pretty much no rules then) and most campers had headed home. We left on October the fifth. Had our area pretty much to ourselves for ten nights. Only an occasional neighbor well away from us. Was told they could not hear it run. Temps were in the teens at night so I left it on all night. Heater ran a lot/ tough on the battery. Fueled it at 9PM and let it run dry the next day. 12:40 PM.  15 hours and forty minutes on one gallon of gas.

We no longer dry camp, but if we did, I would want our Honda in the back of the toad for easy access. Love our Onan diesel water cooled  7.5 KW . Very quiet, but the Honda is the choice for keeping our four 6volt house batteries charged while sleeping. For the Honda, I change the oil on site every 50 hours easily and without making a mess.

Generac makes a 2000i that is cheaper, but for durability Honda is my gold standard.

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In our first class A (1988)  we had an air cooled Onan. It was quite noisey. Do not remember exact size/ maybe 5.5 to 6 kw. It would run both roof top ac, the converter, microwave all at once. Never tried the convection when everything else was running. Probably could not have handled that load. When at altitude in Colorado in the autumn, I had to put a trouble light by the carburetor to keep it from freezing up. If I didn't the unit would stumble and barely run. I have not heard a quiet air cooled Onan anywhere.

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57 minutes ago, obedb said:

In our first class A (1988)  we had an air cooled Onan. It was quite noisey. Do not remember exact size/ maybe 5.5 to 6 kw. It would run both roof top ac, the converter, microwave all at once. Never tried the convection when everything else was running. Probably could not have handled that load. When at altitude in Colorado in the autumn, I had to put a trouble light by the carburetor to keep it from freezing up. If I didn't the unit would stumble and barely run. I have not heard a quiet air cooled Onan anywhere.

I have a Onan Marquis 6.5 LP which is surprisingly quite.

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Talking about two different animals there Desert Deals. What year is your coach? Probably newer with considerable improvement plus propane. Onan Diesel Water Cooled are a quantum leap from what we had in our first coach. Glad that you are happy with it. You would not have enjoyed our 1988 Onan gas unit.

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I believe it was a marquis 6.5 gas I had in last coach it was quiet the whole set was enclosed like the diesels the older ones were all open with no sound attenuation 

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My 10KW is constant speed, the most noise I have ever had, even running down the Highway...each time I get to a Custom Check point, I pull over and turn off AC's, then Genny and resume my approach to the agent, I can hear him, he hears me.  Never have I been asked "why did you pull over?"  Then upon leaving I do the same in reverse.

ObedB.  At the house, on it's own slab, I have a 18KW Generac it runs on Propane and checks it's self each week....my neighbors can't hear it and neither can I in the house above the garage.  Cheaper than Onan!

The last time I filled the tank, is when I bought the Generac, in March 2009...almost 6 months after Hurricane IKE.  I have both Electric and Natural Gas at house, the gas was shut off a week after the storm past!

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Byron.  I had a 1997 Allegro, gasser with 2 AC's , 30A and a Onan 4.0, just depends on how the coach is wired.  I turned off A/C's to run microwave/ convection, same when I was on heat pump! 

Carl

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3 hours ago, obedb said:

Talking about two different animals there Desert Deals. What year is your coach? Probably newer with considerable improvement plus propane. Onan Diesel Water Cooled are a quantum leap from what we had in our first coach. Glad that you are happy with it. You would not have enjoyed our 1988 Onan gas unit.

I have Onan generators in 10 or so different coaches starting with a 69 Lifetime I had in 74.  I've had quite a few different models of Onans but this Marquis is the quietest. It is in a 98 Discovery still 19 years old.

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DD69.  Did not know what coach I was looking at, but it looks good and I really like the colors! :)  We did have some strange named coaches back then! :lol:  I don't remember a Lifetime, was that the Manufacturer or model?  I love it when I see some older rigs still rolling along.

Carl

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An old buddy had a 1988 pace arrow 40 foot, 30 amp service with a 6500 Onan. His was equipped with 2 rooftop ac's, could only run one ac on shore power, to run both ac's, required that the genny to be started.

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11 hours ago, manholt said:

DD69.  Did not know what coach I was looking at, but it looks good and I really like the colors! :)  We did have some strange named coaches back then! :lol:  I don't remember a Lifetime, was that the Manufacturer or model?  I love it when I see some older rigs still rolling along.

Carl

The Lifetime looked like a Winnebago of the 60s.  Boxy with a reverse slope windshield.

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