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 Emerald NHE Idle Problem


this thread has 53 replies and has been viewed 2301 times

Reply
 
Thread Tools Display Modes
  #11  
Old 02-03-2017, 01:43:19 PM
Motorhead's Avatar
Motorhead Motorhead is offline
Subscriber
 
Join Date: May 2007
Location: Central Coast, California
Posts: 3,789
Thanks: 1,779
Thanked 2,588 Times in 1,353 Posts
Default Re: Onan Emerald NHE Idle Problem

Quote:
Originally Posted by Ed III View Post
Concerning adjustments, yes, I did work on adjustments, starting with the factory recommended 1 1/4 turn for the main and 1 turn for the idle.

I removed the large and small jets in the bottom of the bowl area. The small one was stopped up. When I finished, I could see light through both, but they could have a coating making them smaller than factory spec. I was quite cautious due to factory literature warnings. I will check those again.

I know for sure there is only one of the ports described as .010 open. I did not see anymore, so I need to look more closely at that. I am disappointed at the commercial carb cleaner/soak. It did not do a good job.

My generator is in an out building and it is cold and rainy today. I will wait for better weather to proceed, but I will report back on my findings.

If anyone knows, is there anywhere I can find information on cleaning the slip rings? I am uncomfortable removing the brushes.

Thanks,

Ed
I always start with 1.5 turns out on each. I'm sure you are aware that the plastic main jet stop cap is removable. With your set being a somewhat later machine, the EPA was already tightening the screws so to say on stationary equipment too. The carburetors were set up pretty tight fuel wise when new.
__________________
The Control panel
and gauges of my
7.5JB
Reply With Quote
The Following User Says Thank You to Motorhead For This Post:
Sponsored Links
  #12  
Old 02-03-2017, 02:00:49 PM
len k len k is offline
Registered-III
 
Join Date: Jun 2012
Location: Manchester, New Hampshire
Posts: 15,906
Thanks: 427
Thanked 5,758 Times in 4,184 Posts
Default Re: Onan Emerald NHE Idle Problem

I can see your BIG idle mix adjustment screw, the manual talks about how to adjust it. I didn't clean mine and it ran great after I cleaned the heavily plugged main jet tubes. On newer models the EPA made them cover over idle mix adjustment screw and hide it behind an aluminum disk ( that you can easily pry off to adjust it).

Technically you can adjust the newer carbs just like the old ones. But EPA doesn't let the manufactures tell you how to do it, they don't want to take the chance of people adjusting it rich so it will pollute.
(they say JUST buy new $300 carb instead of spending $1 of time fixing old one . What idiot is going to do that?)
Reply With Quote
The Following 2 Users Say Thank You to len k For This Post:
  #13  
Old 02-03-2017, 04:39:09 PM
Ed III Ed III is offline
Registered
 
Join Date: Feb 2017
Location: Florence, South Carolina
Posts: 24
Thanks: 25
Thanked 10 Times in 5 Posts
Default Re: Onan Emerald NHE Idle Problem

Thanks, Pete, Len and Motörhead.

Yes, I have tried choking it, it runs better, but also raises the rpm, so it could just be the rpm increase helping things. When I was diagnosing the regulator, I had no flash voltage or fuel pump voltage, so I jumpered coil and used ether to start it. Don't remember much about how it ran. I can do that again.

I will attach a photo, you can see the M and S ports. They have a ball pressed into them. I had good flow through both areas after cleaning, but not sure it is correct.

Good to know they are hiding adjustments. That may come in handy one day.

Ed
Attached Thumbnails
Click image for larger version

Name:	image.jpeg
Views:	43
Size:	185.8 KB
ID:	273858  
Reply With Quote
  #14  
Old 02-03-2017, 05:25:25 PM
len k len k is offline
Registered-III
 
Join Date: Jun 2012
Location: Manchester, New Hampshire
Posts: 15,906
Thanks: 427
Thanked 5,758 Times in 4,184 Posts
Default Re: Onan Emerald NHE Idle Problem

I wouldn't try removing the pressed in steel balls by M&S to get at the air jets, you'll destroy the casting by time you get the balls out. Besides being a slightly different carb design there may not be unscrewable air jets under them. These are the air jets, on mine they were perfectly clean, gas couldn't get to them to crud them up.

Control board automatically flashed reg/rotor every time you start gen by using the start/stop switch. Control board does this by applying positive ~ 9-12 VDC to pin 7 of reg (VR1).
Reply With Quote
The Following 2 Users Say Thank You to len k For This Post:
  #15  
Old 02-03-2017, 05:55:42 PM
Vanman Vanman is offline
Subscriber
 
Join Date: Aug 2011
Location: Mission Viejo, California
Posts: 4,028
Thanks: 5,157
Thanked 1,717 Times in 1,152 Posts
Default Re: Onan Emerald NHE Idle Problem

Quote:
Originally Posted by Ed III View Post
... The power plant started surging, so I hired someone to repair it. I noticed after repair that I was getting 130 volts instead of 120. Well, in hindsight, it appears to stop the surging, he upped the rpm, which of course upped the cps as well as the voltage...
It would seem that "repairman" may have turned in the idle speed screw (which normally never touches anything as the engine never idles, instead always running at ~1800 rpm) in order to stop the hunting. Obviously this is not a solution!

After you properly repair it and it's once again running properly, you'll want to reset that idle screw as per the manual to the correct speed. (have to hold the throttle in idle against the governor spring to make that adjustment. When you let go it will jump back up to 1800 rpm).

Keith
Reply With Quote
The Following User Says Thank You to Vanman For This Post:
  #16  
Old 02-03-2017, 05:57:09 PM
Motorhead's Avatar
Motorhead Motorhead is offline
Subscriber
 
Join Date: May 2007
Location: Central Coast, California
Posts: 3,789
Thanks: 1,779
Thanked 2,588 Times in 1,353 Posts
Default Re: Onan Emerald NHE Idle Problem

I second len k. That carburetor body could have been used for many other applications, NON Onan. Pull the plastic cap off of the low speed jet or at least cut off the tab so you can adjust it. It really isn't that hard to remove the generator brush holder to get to the slip rings. I have a late, 4BGE, same basic configuration and I remove the brush holder, ground the trigger side of the coil and use the starter to turn the assembly and CAREFULLY hold a fine piece of polish paper or Scotchbrite to clean the rings.
I, not being familiar with your particular model, would say that the no voltage issue to the coil and fuel pump could be that the generator is not making electricity due to dirty slip rings or bad vpltage regulator, if it has one.
__________________
The Control panel
and gauges of my
7.5JB
Reply With Quote
  #17  
Old 02-03-2017, 06:22:39 PM
len k len k is offline
Registered-III
 
Join Date: Jun 2012
Location: Manchester, New Hampshire
Posts: 15,906
Thanks: 427
Thanked 5,758 Times in 4,184 Posts
Default Re: Onan Emerald NHE Idle Problem

Spec D and above on BGE/NHE have electronic reg.
Spec A, B, C had the current transformer voltage booster by starter ( not a real reg).

I haven't seen your gen in person , but I see the idle mix adjustment have a philips head screw on it , plastic maybe. So you may not have pry anything off to adjust it , just stick a philps screwdriver in it and try to rotate. Think the intial setting for idle mix adjustment is ~ 1.25 turns off the seat , read manual. There is a separate setting for the separate idle RPM stop screw
Reply With Quote
  #18  
Old 02-03-2017, 06:53:50 PM
Ed III Ed III is offline
Registered
 
Join Date: Feb 2017
Location: Florence, South Carolina
Posts: 24
Thanks: 25
Thanked 10 Times in 5 Posts
Default Re: Onan Emerald NHE Idle Problem

Thanks to all. Just to refresh, all issues are resolved except for cleaning the slip rings and failure to idle. The regulator problem is now history. I have a pretty good grasp as to how the regulator and control board fit into the scheme.

The carb has been completely disassembled for the cleaner dip/ soak, so all adjustment screws were removed as were the plastic covers. The covers are not likely to return. I don't expect carb adjustment to be a problem once it is working correctly.

I will try the brush removal to clean the slip rings. What makes me nervous is that I have done the same in other applications and it was difficult to hold everything ........... Springs, etc, in place for reassembly. Some were in confined areas and required a special tool for reassembly.

Thanks again for your interest and help.

Ed
Reply With Quote
  #19  
Old 02-03-2017, 08:09:24 PM
Motorhead's Avatar
Motorhead Motorhead is offline
Subscriber
 
Join Date: May 2007
Location: Central Coast, California
Posts: 3,789
Thanks: 1,779
Thanked 2,588 Times in 1,353 Posts
Default Re: Onan Emerald NHE Idle Problem

Ed, The brush holder assembly might have a small hole at the slip ring side to put a small wire like a paper clip to hold the brushes in until you put the screws back in. I can't remember..... C.R.S. = Can't Remember S#!t
__________________
The Control panel
and gauges of my
7.5JB
Reply With Quote
The Following User Says Thank You to Motorhead For This Post:
  #20  
Old 02-03-2017, 08:55:20 PM
Ed III Ed III is offline
Registered
 
Join Date: Feb 2017
Location: Florence, South Carolina
Posts: 24
Thanks: 25
Thanked 10 Times in 5 Posts
Default Re: Onan Emerald NHE Idle Problem

Quote:
Originally Posted by Motorhead View Post
Ed, The brush holder assembly might have a small hole at the slip ring side to put a small wire like a paper clip to hold the brushes in until you put the screws back in. I can't remember..... C.R.S. = Can't Remember S#!t

I will try it, hopefully tomorrow. I can likely do it, I just remember past difficulties.

Thanks,

Ed
Reply With Quote
Reply


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 Emerald I Genset Spark Problem Saulfun1971 Magnetos, Ignition Coils and Spark Plugs 2 06-13-2016 12:26:10 PM
Onan Emerald 1 GenSet wont idle Crreedplumbing Onan Generators 3 05-30-2016 12:02:23 AM
onan emerald 1 voltage problem brhoads Onan Generators 7 04-04-2014 12:36:01 AM
HELP!! Problem with Onan Emerald 1 Genset dillon Onan Generators 13 07-16-2012 10:56:58 AM
Onan Emerald 6500 Won't Idle Smoothly? Willie B Onan Generators 28 03-17-2012 09:32:27 PM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 01:26:10 AM.

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