Generators and Motors
[Home] - [HELP] - [Forums] - [Library] - [Photo Gallery] - [Groups] - [Classified Ads] - [Subscribe] - [Links] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Vintage Electrical Equipment > Generators & Electric Motors General Discussion > Onan Generators
Forgot Password? Join Us!

Notices

Onan Generators Restoring, operating and maintaining vintage Onan generators.

Onan Generators

Onan MDJF stops released start switch Centrifugal Switch Problem


this thread has 10 replies and has been viewed 1392 times

Reply
 
Thread Tools Display Modes
  #1  
Old 01-28-2015, 09:16:17 PM
Chuck711 Chuck711 is offline
Registered
 
Join Date: Jan 2015
Location: New Bern, North Carolina
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Default Onan MDJF stops released start switch Centrifugal Switch Problem

Onan MDJF Diesel Generator stops when released start switch.

I jumped Centrifugal Switch wiring ( added on/off toggle )

and unit runs ok

What could my problem be ?

The plunger is good.

Chuck
Reply With Quote
Sponsored Links
  #2  
Old 01-28-2015, 09:37:43 PM
Nazrat Nazrat is offline
Registered-II
 
Join Date: Aug 2007
Location: Upstate, VA
Posts: 400
Thanks: 46
Thanked 69 Times in 46 Posts
Default Re: Onan MDJF stops released start switch Centrifugal Switch Problem

Sounds to me like you need to adjust the gap in the centrifugal switch. Disconnect it first as it is live with the engine off. Once it is disconnected, remove the wing nut and cover and you'll see the hex head on the adjuster under the contact.

-Tad
Reply With Quote
  #3  
Old 01-28-2015, 09:53:08 PM
Chuck711 Chuck711 is offline
Registered
 
Join Date: Jan 2015
Location: New Bern, North Carolina
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Default Re: Onan MDJF stops released start switch Centrifugal Switch Problem

Tad
The contact are clean with gap.
Upon increasing RPM the contacts close as should then when start switch is released
the contacts open up and engine stops
Reply With Quote
  #4  
Old 01-28-2015, 10:28:29 PM
Nazrat Nazrat is offline
Registered-II
 
Join Date: Aug 2007
Location: Upstate, VA
Posts: 400
Thanks: 46
Thanked 69 Times in 46 Posts
Default Re: Onan MDJF stops released start switch Centrifugal Switch Problem

See if the gap is at .020"
Reply With Quote
  #5  
Old 01-29-2015, 12:46:34 AM
BigBlockChev's Avatar
BigBlockChev BigBlockChev is offline
Subscriber
 
Join Date: Jan 2007
Location: Coquitlam, BC, Canada
Posts: 2,158
Thanks: 398
Thanked 1,691 Times in 981 Posts
Default Re: Onan MDJF stops released start switch Centrifugal Switch Problem

Do you have a Hz setting on your Multimeter or better still a KIll a watt. If you do, see what the Hz is when it is shutting down, maybe your governor is set too high or the engine IS actually running too fast. Hz should be in the 60ish range for the engine to be turning around 1800 rpm. It is easy enough to adjust the locknuts on the front of the engine. They are just below the plate that the water pump is bolted to. Cheers Dan
Attached Thumbnails
Click image for larger version

Name:	mdja.jpg
Views:	33
Size:	74.5 KB
ID:	217206  
Reply With Quote
The Following User Says Thank You to BigBlockChev For This Post:
  #6  
Old 01-29-2015, 08:35:33 AM
Max Thompson Max Thompson is offline
Sponsor
 
Join Date: May 2009
Location: N.W. Missouri, USA
Posts: 6,034
Thanks: 5,366
Thanked 5,763 Times in 3,060 Posts
Default Re: Onan MDJF stops released start switch Centrifugal Switch Problem

Are the contacts "clean". They are like ignition points & must make good contact. Also check all connections from the switch back to the control box. On the J series sets I have seen, they all have spade connectors in line to the centrifugal switch and these are notorious for becoming brittle, cracking & not making contact.
Reply With Quote
  #7  
Old 01-29-2015, 10:43:37 AM
Chuck711 Chuck711 is offline
Registered
 
Join Date: Jan 2015
Location: New Bern, North Carolina
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Default Re: Onan MDJF stops released start switch Centrifugal Switch Problem

Yes Contacts are good on Start Relay and Centrifugal Switch

Cannot understand why works well when I eliminate Centrifugal Switch using toggle switch
Reply With Quote
  #8  
Old 01-29-2015, 12:41:54 PM
Max Thompson Max Thompson is offline
Sponsor
 
Join Date: May 2009
Location: N.W. Missouri, USA
Posts: 6,034
Thanks: 5,366
Thanked 5,763 Times in 3,060 Posts
Default Re: Onan MDJF stops released start switch Centrifugal Switch Problem

Quote:
Originally Posted by Chuck711 View Post
Yes Contacts are good on Start Relay and Centrifugal Switch

Cannot understand why works well when I eliminate Centrifugal Switch using toggle switch
Because somewhere in the system, power is not making it from one side of the centrifugal switch back to the ignition / start disconnect relay.

If you are plugging your "jumper switch" into the spade connectors at the centrifugal switch to make it work, this only leaves one component out of the loop, the centrifugal switch.

Have you tried cleaning the contacts on the centrifugal switch with fine sand paper?

Last edited by Max Thompson; 01-29-2015 at 04:46:43 PM. Reason: clean contacts
Reply With Quote
  #9  
Old 01-29-2015, 01:01:46 PM
Kpack
Guest
 
Posts: n/a
Default Re: Onan MDJF stops released start switch Centrifugal Switch Problem

Quote:
Originally Posted by Chuck711 View Post
Yes Contacts are good on Start Relay and Centrifugal Switch

Cannot understand why works well when I eliminate Centrifugal Switch using toggle switch
I had to hold mine shut once with a broom handle to get it to hold on my jc. I don't know why they won't hold sometimes. Yours my be different from mine. In the picture out of my manual it tells in a emergency you can short it
Attached Thumbnails
Click image for larger version

Name:	image.jpg
Views:	45
Size:	160.2 KB
ID:	217241  
Reply With Quote
  #10  
Old 01-29-2015, 03:14:36 PM
Max Thompson Max Thompson is offline
Sponsor
 
Join Date: May 2009
Location: N.W. Missouri, USA
Posts: 6,034
Thanks: 5,366
Thanked 5,763 Times in 3,060 Posts
Default Re: Onan MDJF stops released start switch Centrifugal Switch Problem

Quote:
Originally Posted by Kpack View Post
In the picture out of my manual it tells in a emergency you can short it
I "think" this is what he is doing with the toggle switch.
Reply With Quote
Reply

Bookmarks


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

F o r u m Jump

Similar Threads Chosen at Random
Thread Thread Starter F o r u m Replies Last Post
onan 4.0 bf dies when start switch released need advise YellowLister Onan Generators 19 11-02-2014 10:04:51 PM
Onan 4k start/stop light doesnt work and stops running when release start switch JoshD Onan Generators 12 09-06-2014 07:51:40 AM
Onan 6.5 nhe starts but stops when switch is released Max Thompson Onan Generators 17 01-30-2013 01:15:26 PM
Onan 6.5NH 3CR/16004P Won't stay running after the start switch is released. Hudson69 Onan Generators 6 07-18-2012 06:17:03 PM
Onan stops when I let off the start switch shadetree13 Onan Generators 15 10-21-2011 06:56:52 PM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 08:15:51 PM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark - A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2016 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277