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Onan 6.5nh Points Problem and Points Replacement and Adjustment


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  #1  
Old 11-05-2017, 01:24:31 AM
mvimpvm mvimpvm is offline
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Default Onan 6.5nh Points Problem and Points Replacement and Adjustment

Hi guys,

I have a 6.5NH that has been giving me fits. I have never figured out how to adjust the timing and the points on a 6.5NH. Looked on youtube, looked here, but never really found anything that truly walked me through the process on an onan bfa or nh. The reason it came up was I am trying to do a tri-fuel conversion but having all kinds of issues. I dropped the tri-fuel conversion and am just trying to get it to run properly on gas. I think the points are pretty well shot but wanted to check with you all first. The two sides of the points SHOULD be flat correct? Mine aren't. I figured something is going wrong and metal from one side is being deposited on the other side. Probably a bad condensor. If I replace the points, how do I adjust them? Can anyone walk me through that process? Yes, I have the manual but that really isn't that helpful for someone that hasn't done that before. Is the only adjustment just to get the gap correct? Is that done by loosening the allen screws and sliding it back and forth to get the correct gap? I would love it if someone would post a youtube video on what that process actually looked like.

The 6.5 is idling fine but under a hard load running like crap.
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Old 11-05-2017, 02:21:54 AM
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Default Re: onan 6.5nh points problem and points replacement and adjustment

1. Remove the ignition point assembly and carefully file the points flat.

2. Place your finger on the vertical pushrod that activates the points.

3. Using a break-over bar, extension and socket, rotate the engine
crankshaft. (Access the flywheel bolt thru the engine cooling scroll)

4. Rotate the engine until the point push rod is at its highest point.

5. Install the points and set the gap to .020" with the point gap adjusting
screw.

You're right. The consenser is probably causing the metal transfer and the misfire.
You probably ought to replace both the points and the condenser.
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Old 11-05-2017, 05:16:19 AM
armandh armandh is offline
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Default Re: onan 6.5nh points problem and points replacement and adjustment

the points run off a cam lobe and there is no real "timing" adjustment.
however, the timing is slightly varied as the point gap changes

raising the adjustable but non moving point to a smaller gap
causes the points to open slightly later.

thus use the correct gap
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Old 11-05-2017, 09:32:12 AM
JohnnyC JohnnyC is offline
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

All good information that was posted by others. A common problem that sometimes happens is the 2 piece intake manifold develops a leak between the two halves and needs to be resealed. It is an easy, but time consuming job, so take care of the points and condenser first.

What are your plans for converting to tri-fuel? I did this to my 6.5NH with excellent results and requires absolutely NO modifications to the carburetor.

JohnnyC
New Jersey
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Old 11-05-2017, 10:03:52 AM
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

The only timing on the NH is by setting the gap. On other units such as the CCK. You can set the timing by moving the point box along with the gap. Do as Lokay5 posted you should have no problem.

The intake manifold problem. Mainly showed up on a certain production run. But it is a good idea to check for leaks.
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Old 11-05-2017, 12:40:11 PM
mvimpvm mvimpvm is offline
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Default Re: onan 6.5nh points problem and points replacement and adjustment

EXACTLY what I needed. I read about adjusting the timing and for the life of me could not figure out how to do that. I can gap points. Got really good at it with a 65 Olds, 72 Buick, and a 71 Ford. I can adjust timing by twisting a distributor but no such beast here. Got it. I will replace both the points and the condensor. I seem to remember there was a shift in production of the points and condensor and that the older ones were a lot better than the newer ones. Anyone got any advice on better vs not so good points and condenser?
I
n my rebuild I was pretty thorough on checking both the carb and intake manifold for leaks. I remember reading somewhere it is best not to separate that. Don't think I did. Will check with a bit of propane to make sure there are no leaks anywhere.

The tri-fuel is my goal. Well, end goal. I have the complete setup but am still having trouble with it dying when running on propane or natural gas about five minutes into running. I am going to go back to an old thread and repost my issue with youtube video once I get this worked out. If the points are a problem they will be a problem with tri-fuel so I figured I would get this worked out first.
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Old 11-05-2017, 12:51:41 PM
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Default Re: onan 6.5nh points problem and points replacement and adjustment

For cleaning points I like to fold a strip of good grade 180 sandpaper in half and drag it thru the points. Don't know if the angles will let you do that on a NH
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Old 11-05-2017, 03:02:44 PM
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

There is enough crud on the points that I will need a file to get it off. I have a super small flat file I wil try to get it flat. Wish there was a good source of the reco points around.
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Old 11-05-2017, 03:48:25 PM
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

I remember reading an old car manual that said if you have material transfering from one points surface to the other it has to do with condensor value (MFD) being too high or low. Shows up as spike on one surface and hole in other.

Wrong value is most likely condensor went bad and is low or zero capacitance.
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Old 11-05-2017, 08:29:12 PM
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

Well, tried to file the points and the angles were all wonky. Give me a week and I will report back as soon as I get new points and condenser in.
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Old 11-05-2017, 08:33:30 PM
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

For now if you need it to run maybe just remove points and file in your hand. Might try Staker named Onanparts for new points, he sells lot of new stuff.
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Old 11-06-2017, 06:06:07 AM
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

that is where I bought mine [newer style]
https://onanparts.com/

I had a bad connection between the point contact and spring [tightened crimp]
also the other point and the adjustment lever [soldered at the back]

this is now a spare.
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Old 11-06-2017, 11:47:29 AM
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

OnanParts is fishing till like Dec. 5th and not taking orders from his web sight.
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Old 11-07-2017, 05:09:14 AM
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

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Originally Posted by mvimpvm View Post
Well, tried to file the points and the angles were all wonky. Give me a week and I will report back as soon as I get new points and condenser in.

STEP #1-

Remove the ignition point assembly and carefully file the points flat.
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Old 11-25-2017, 09:12:43 PM
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

Update--11/25/2017 Well, was off for a bit so I had some time to play around with the 6.5NH. For once I have good news. Ordered new points and condenser a couple of weeks ago. Upon disassembly I discover the condenser was bad and speced about 5X the normal spec of 0.3 microfarads. Mine was around 1.5 microfarads which would explain the nasty crusty points. Replaced both and ordered spares. Adjusted the points back to 0.016 inches and started it up. Ran like crap. Arrghh!! Even worse than before actually. Decided to double check the carburetor and discovered that the idle mixture screw was turned out 5 complete turns. Well, that was a problem so I fixed that one as well. Did the complete carburetor adjustment procedure and it works! Perfectly, actually. Runs like a champ. Did a cold sweat test three different times from no load to full load under gasoline and it purrs. For kicks and giggles I ran it dry of gasoline, disconnected the fuel pump, and put the gaseous adapter back on top of the carburetor to run it under propane. It started right up. Had to tweak the load block a bit but it runs great. It started surging again but then I looked at the load block and notice it had vibrated completely out of adjustment so I put it back in spec and the surging and hunting went away. Turns out points and condenser really matter. (Shock, huh!) One questions and a statement.

1. I REALLY appreciate all your help. I have actually been fighting this issue for several years now across several generators. Thank you from the bottom of my heart to all of you that have contributed.

2. Question. Now that I have this thing running I don't want to burn up my valves by running it lean on NG or Propane. I am assuming in an ideal world you bias NG or Propane a bit rich. How do you all adjust your load blocks when running on gaseous fuels? I have adjusted mine to be what I feel to be on the rich side but I am curious how you all do that? I remember seeing a post about that but couldn't find it anywhere.
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Old 11-26-2017, 03:41:37 PM
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Default Re: onan 6.5nh points problem and points replacement and adjustment

Lokay, I was rereading your post and notice you mention adjusting the points to 0.020 inches. The book says 0.016. I was curious about the difference. Just rounding? Run better at that gap?
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Old 11-26-2017, 09:29:35 PM
Chas183 Chas183 is offline
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

Gaseous fuels should be set lean.
The gaseous fuels tend to burn in the exhaust when rich.
It's the opposite of gasoline.

chas183
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Old 11-27-2017, 03:51:05 PM
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

Well, that is why I ask questions. Always learning. How do you adjust your load block?
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Old 11-28-2017, 12:11:05 PM
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Default Re: Onan 6.5nh Points Problem and Points Replacement and Adjustment

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Originally Posted by mvimpvm View Post
... Had to tweak the load block a bit but it runs great. It started surging again but then I looked at the load block and notice it had vibrated completely out of adjustment so I put it back in spec and the surging and hunting went away. ...
They sell a weak Locktite thread locker just for adjustment threads so they don't move on their own, but can easily be re-adjusted.
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