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Old 04-23-2020, 07:17 PM   #11
KRatcliff
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Default Re: Onan QG 4000 RPM

Thanks for the info. I went with the recommended 150 hours for hot, dusty conditions which described sportsman parking in Division 4 and many of the others.
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Old 06-11-2020, 10:28 PM   #12
Ed Carpenter
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Default Re: Onan QG 4000 RPM

Quote:
Originally Posted by Rich Biebel View Post
They are my favorite model and I own 2 myself....

Most Every Class C Motorhome has one.....

I have one in my trailer and one in my Class C Motorhome....

They are not like the older 1800 rpm units for sure and are far less durable.

Older models were twin cylinder flathead engines that ran 1800
From a 4 to a 7 KW

20 years ago they started making their modern versions....

Single cylinder 3600 rpm....on the QG 4000's......The 5.5 and 7kw's are twin cylinder and nothing like the 4's....

Onan stopped making their own engines back then and everything they build uses an import built engine......No big surprise....

For those that don't know.....
A modern Onan QG 4000 has NO low oil shutdown....
If it runs low on oil it will at the very least seize up and usually much worse.....

The aluminum rod usually blows up and takes out the engine.

They only hold about 1-1/2 quarts of oil and it should be changed often.....and checked often.....No filter.....splash oil....

I saw more than one that blew up and really busted up everything in there.....changing an engine is not a good option so it winds up being trashed....
Good to know. I just bought 28’ trailer extra height. Looking at getting a generator. No a/c right now but want to put 2 15 units in it. So it will have that plus lights, plugs for charger air compressor etc. would an Onan 4000 be enough? Thanks Ed
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Old 06-12-2020, 10:01 AM   #13
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Default Re: Onan QG 4000 RPM

I have noticed more racers are going to the inverter style generators like the Honda EU7000iS and the Honda EU3000iS.

They are very quiet and only run as many RPM as they need to cover the load.

However they appear to need to have the generator door opened and pulled out on a slide to get proper cooling.

Connecting an exhaust pipe on the EU3000iS may take a special kit.

Of course these generators are pretty expensive but other inverter generator are starting to show up on the market.

However the Onans are not inexpensive either.
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Old 06-13-2020, 12:05 PM   #14
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Default Re: Onan QG 4000 RPM

Quote:
Originally Posted by Ed Carpenter View Post
Good to know. I just bought 28’ trailer extra height. Looking at getting a generator. No a/c right now but want to put 2 15 units in it. So it will have that plus lights, plugs for charger air compressor etc. would an Onan 4000 be enough? Thanks Ed
4000 is barely enough for a trailer. I put a 6.5 in mine and it runs everything very easily. I bought an old Onan 6.5 with low hours for $500. It’s one of the 1800 rpm twin cylinder units. They are very quiet and reliable. Just search on Craig’s list or Facebook marketplace. There are usually some for sale there.
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Old 06-13-2020, 10:09 PM   #15
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Default Re: Onan QG 4000 RPM

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Originally Posted by Mike Pearson View Post
4000 is barely enough for a trailer. I put a 6.5 in mine and it runs everything very easily. I bought an old Onan 6.5 with low hours for $500. It’s one of the 1800 rpm twin cylinder units. They are very quiet and reliable. Just search on Craig’s list or Facebook marketplace. There are usually some for sale there.
Ok thanks. I’ve found a few used in my area.
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Old 06-14-2020, 10:20 AM   #16
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Default Re: Onan QG 4000 RPM

What are the model numbers for the low RPM (1800) Onan 6.5 RV gensets?

Anything to look for when shopping for one?

Thanks!
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Old 06-14-2020, 03:52 PM   #17
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Default Re: Onan QG 4000 RPM

The older units have not been produced for about 20 years so any one you buy is at least that old.

The common models were BGE, NHM, NHE

The best ones were with black sheet metal covering the entire unit and they had electronic governors

BGE's are the most common. Usually green. Mechanical governors. Made in 4000-5000 and I think some 6500's

The date the machine was made is in the serial number.....First 4 numbers are year and month...

The older ones had points for ignition mounted in a box on top.

You would generally say the newer versions with electronic ignition triggering are more desirable.....BUT in reality they are not...

Mice love to nest in those units and they get in the control box and the lower portion of the generator itself. The ignition rotor device is plastic and is mounted between the rotor and engine and can and will easily be broken hitting anything the mice pile up in there.

Now you have to split the unit apart to replace the plastic ignition component. It is a flying magnet type...…

A points style unit is immune to that problem and the points are easy to change, clean, adjust.....

The old ones were built when Onan still built their own engines.....Very heavy duty and long life. They do have some issues like carbon buildup and various components that can fail but are good.

I own 2 New style 4000's and my trailer unit has many hours on it and has been fine. I use it anytime I'm racing all day pretty much everyday....

It will power all my lights including 500 watt quartz outside and interior fluorescents.....and a portable compressor....

The 4000 in my Motorhome runs a 15,000 BTU AC and a Microwave and a battery charging converter all at the same time with no problem and power to spare.....

I've seen many older units for sale on various sites and often they are SPRAY PAINT rebuilds......A can of Onan green paint is all they got after getting cleaned up....

Some major components are obsolete for the old ones and that's another problem...…

2000 was about when they stopped building the old flathead style units....

Onan engines were used in a long list of industrial applications. Welders, pumps, machines of all kinds and that basic design engine was made for years and years....
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Old 06-16-2020, 07:31 PM   #18
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Default Re: Onan QG 4000 RPM

The one i had in my trailer before the 6.5 was a 4.0 CCK. On the name plate it said
Onan division of Studebaker. It still ran and made power when I pulled it out. I bet it has 20k hours on it.
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Old 06-23-2020, 01:33 PM   #19
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Default Re: Onan QG 4000 RPM

If anybody is looking for a 4000 I have one.I bought it new to replace the one in our Class C and after 3 seasons it quit charging. A trip to the Onan Bridgeway dealer told me it was un reparable. I bought another new one, but while waiting on it to come in I went ahead and had a look at my old ( torn apart from Onan) unit. All that had happened, is the brushes had worn, twisted inside the brush holder, and mangled up one of the two small wires going to the brushes. Other than some of the insulation being removed from the wire, it was usable. I just put some small heatshrink on the wire, bought a new brush holder/brush set, and re assembled. It ran flawlessly on the bench and charges just fine. The thing looks new, its not even dirty. I'd like to get it out of my road , its here in the garage .. 700.00

740 297 0817
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Old 06-23-2020, 06:22 PM   #20
Rich Biebel
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Default Re: Onan QG 4000 RPM

I pulled one out of a 2010 Class C today..

Around 2000hrs on it. Starter broke but the machine is a mess and had NO oil in it. I turned it over by hand at the blower wheel and it has NO compression. With no oil it probably broke the connecting rod.

Repairing the engine on a machine in extremely poor condition makes zero sense. It could have destroyed a lot inside that engine and replacing the complete engine is an even worse idea from a cost standpoint.

I ordered the owner a new machine. I will go pick it up as soon as it's ready for pickup and install it...1 or 2 days at most

The owner will be happy.....New generator.....But sir, please check the oil and leave the access door in place !!!

It says both things in big bold letters right on the front.....

A new style 4KY 4000 watt Onan does NOT have a low oil level shutdown....it will break the engine's connecting rod every time when oil gets so low that there is nothing visible on the dipstick....Seen it many times.....ZERO maintenance....for 2000hrs ? I am not sure on that one....

The owner actually asked me if the machine has oil in it like a car engine !!!
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