GMCforum
For enthusiast of the Classic GMC Motorhome built from 1973 to 1978. A web-based mirror of the GMCnet mailing list.

Home » Public Forums » GMCnet » Is the 4k power drawer a "GOOD" generator?
Is the 4k power drawer a "GOOD" generator? [message #83891] Mon, 10 May 2010 06:36 Go to next message
hertfordnc is currently offline  hertfordnc   United States
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
Senior Member
Given the lower capacity and the age it is hard to glean from this forum whether or not the 4K is decent unit. People seem to grumble about it quite a bit.

I have one from my parts project and I am pondering what to do with it.

I haven't started it yet but old receipts suggest it was well maintained and I'm guessing it will run OK.

The Revcon comes with a 5k Onan CCK. The antique motor guys (http://www.smokstak.com/ ) tell me this is a really great generator. It is big and heavy and apparently runs forever.

It is also twice as big as the GMC. I could gain some valuable external storage space and have the advantage of slide out access if i switch generators.

With the higher capacity the CCK might be a better candidate for backup house power.

Also, somewhere I saw a page on how to run the Onan without a control board, but I can't find it.


Thanks

dave


Dave & Ellen Silva Hertford, NC 76 Birchaven, 1-ton and other stuff Currently planning the Great american Road Trip Summer 2021 It's gonna take a lot of Adderall to get this thing right.
Re: [GMCnet] Is the 4k power drawer a "GOOD" generator? [message #83894 is a reply to message #83891] Mon, 10 May 2010 06:56 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
Dave,

I abandoned my 4k several years ago, so this is a reasonably unbiased
opinion: It's a good unit. Sturdy and long-lived. My opinion, that most
of the problems I had with it in the GMC were heat related, is fortified by
the fact that my son now uses it, mounted on a trailer, for emergency backup
power for his home. He hasn't run it nearly as much as I did, but has had
NO trouble with it; my troubles usually began after hours of running in HOT
weather. Sorta wish I still had it.

Maybe you can vent it better in the Revcon's larger compartment.

I'd run it without a control board only if I included a low oil shutdown
feature.

Ken H.


On Mon, May 10, 2010 at 7:36 AM, dave silva <gmc@davesilva.com> wrote:

>
>
> Given the lower capacity and the age it is hard to glean from this forum
> whether or not the 4K is decent unit. People seem to grumble about it quite
> a bit.
>
> I have one from my parts project and I am pondering what to do with it.
>
> I haven't started it yet but old receipts suggest it was well maintained
> and I'm guessing it will run OK.
> ...
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist



Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] Is the 4k power drawer a "GOOD" generator? [message #83906 is a reply to message #83894] Mon, 10 May 2010 08:29 Go to previous messageGo to next message
hertfordnc is currently offline  hertfordnc   United States
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
Senior Member
Thanks-

Now can anyone point me to the link i saw about running it without the control board?

I seem to remember that page having a lot of good info on how everything works and I am pretty clueless.

thanks



Dave & Ellen Silva Hertford, NC 76 Birchaven, 1-ton and other stuff Currently planning the Great american Road Trip Summer 2021 It's gonna take a lot of Adderall to get this thing right.
Re: [GMCnet] Is the 4k power drawer a "GOOD" generator? [message #83910 is a reply to message #83906] Mon, 10 May 2010 08:50 Go to previous messageGo to next message
wally is currently offline  wally   United States
Messages: 643
Registered: August 2004
Location: Omaha Nebraska
Karma: 5
Senior Member
hertfordnc wrote on Mon, 10 May 2010 08:29

Thanks-

Now can anyone point me to the link i saw about running it without the control board?

I seem to remember that page having a lot of good info on how everything works and I am pretty clueless.

thanks



This might be what you are looking for
http://www.gmcws.org/Tech/dsimmons/onan/onan.html
I've had a 4k Onan out of an RV for years and use it for backup power. It's run for days that way an is relatively quiet compared to other emergency type generators. It's on a cart with a gas hose long enough to drop in a car gas tank through the fill opening.


Wally Anderson
Omaha NE
75 Glenbrook
Re: Is the 4k power drawer a "GOOD" generator? [message #83914 is a reply to message #83891] Mon, 10 May 2010 09:01 Go to previous messageGo to next message
WayneB is currently offline  WayneB   Canada
Messages: 233
Registered: July 2008
Location: Ontario, Canada
Karma: 0
Senior Member
Mine works OK, its the later model with electronic ignition.
it seems to cope well with the smallish demands my 23' places on it, running the roof A/C and the Microwave etc.

Like the rest of the vehicle its an older design though so I guess alot of modern generators by Honda etc would out perform it and be more reliable.


1976 23' GMCII By Explorer

[Updated on: Mon, 10 May 2010 09:04]

Report message to a moderator

Re: Is the 4k power drawer a "GOOD" generator? [message #83915 is a reply to message #83891] Mon, 10 May 2010 09:07 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
Senior Member
hertfordnc wrote on Mon, 10 May 2010 07:36

Given the lower capacity and the age it is hard to glean from this forum whether or not the 4K is decent unit. People seem to grumble about it quite a bit.

I have one from my parts project and I am pondering what to do with it.

I haven't started it yet but old receipts suggest it was well maintained and I'm guessing it will run OK.

The Revcon comes with a 5k Onan CCK. The antique motor guys (http://www.smokstak.com/ ) tell me this is a really great generator. It is big and heavy and apparently runs forever.

It is also twice as big as the GMC. I could gain some valuable external storage space and have the advantage of slide out access if i switch generators.

With the higher capacity the CCK might be a better candidate for backup house power.

Also, somewhere I saw a page on how to run the Onan without a control board, but I can't find it.

Thanks

dave

Dave,

If the unit you have requires no major parts (read $$$), I would hang onto it. You can get a control board, but you only really need it to run the unit from a simple switch. If you are willing to set up separate ignition and start, it is relatively simple.

Those old Onans were designed for long life. With decent maintenance, they run a very long time.

People grumble about them, because once they are left to go bad, they can be very hard to recover to a reliable state.

Mine has been just great for the years I have owned it, and just now the electric end has a problem that I have to pull the unit to diagnose.

Matt




Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: Is the 4k power drawer a "GOOD" generator? [message #83932 is a reply to message #83891] Mon, 10 May 2010 11:10 Go to previous messageGo to next message
Rick Denney is currently offline  Rick Denney   United States
Messages: 430
Registered: January 2004
Karma: 0
Senior Member
The Onans are traditional generators. They provide their surge capability through mechanical inertia, and they produce power using a traditional sine-wave generation unit. That system works pretty well, and the 4K Onan will provide all the power a 30-amp motorhome needs.

There are three major systems on the Onan: The engine, the generator, and the control system. There are some common issues with all three, but I think the piece that really confounds owners is the control system. The wiring, wiring terminations, and the relay-driven control board are subject to flakiness.

On the engine, two process work too make the Onan lose reliability. One is that the engine is often ignored and poorly maintained. When I bought my coach, the Onan had no air filter, a leaking exhaust system, and it sprayed oil all over the back end of the coach. If the lack of an air filter is any measure, the Onan had been left unmaintained for a long time.

The other engine-degrading process is the ignition system, though it's easy to replace that with an electronic ignition.

The generator itself is pretty bullet-proof, except for easy repairs like the bridge rectifier.

Once in a state of good maintenance, the Onans are great. But, as Matt says, it often takes a LOT to get them into a state of good maintenance. Most of the time, I was just trying to get mine to work, so I could go back to playing with the 455, which is the engine that interests me more. Once an Onan has gone down, it's hard to bring it back.

For 23' coaches, though, it might be worth bringing back an Onan unless it's really trashed. The alternatives are few and not much better. In the larger compartment of a 26' coach, there are many better options.

The problems with mine made it too much of a problem on the coach, but I gave it to Jim Washburne who gave it to a buddy who used it for a long time providing power at a hunting cabin. There, it didn't matter if it had to be manually started or if it leaked oil.

Rick "who wishes his Onan hadn't been so far gone" Denney


'73 Glacier 230 "Jaws"
Re: [GMCnet] Is the 4k power drawer a "GOOD" generator? [message #83986 is a reply to message #83910] Mon, 10 May 2010 19:56 Go to previous message
mike miller   United States
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
Senior Member
wally wrote on Mon, 10 May 2010 06:50

... I've had a 4k Onan out of an RV for years and use it for backup power. ... It's on a cart with a gas hose long enough to drop in a car gas tank through the fill opening.


That (the gas hose) is a simple and excellent idea.

Combined with dual fuel (gasoline and propane/natural gas) set-up it would be as flexible as you can get for natural disasters.

All Onans from the 70's are good, but heavy, generators. A bit un-efficient and generally underrated... unlike most modern generators. BUT... They are 60's and older technology, so they require maintenance just like cars and trucks of the same time frame. (Come on... flat heads?)

Do not spend lots of money on it but if it works, keep it!


Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo' http://m000035.blogspot.com
Previous Topic: 16 inch wheel search results.
Next Topic: Pullers and other tools for rent. AutoZone
Goto Forum:
  


Current Time: Sat Nov 02 14:34:50 CDT 2024

Total time taken to generate the page: 0.01296 seconds