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Onan 6.5 NHEFA wont stay running


my onan 6.5 NHEFA26100E sn#j880170695 wont stay running with out holding start button as soon as...

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  #1  
Old 10-22-2010, 09:49 PM
dr fusion dr fusion is offline
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Default Onan 6.5 NHEFA wont stay running

my onan 6.5 NHEFA26100E sn#j880170695 wont stay running with out holding start button as soon as you release start button it dies, pos side of coil has no power. if you hook up 12 volts from battery to + side of coil it will run but surges badly maybe from 900 rpm back to 1800 then back again what should i look at next? been sitting for about 4 yrs. has oil pressure 40 psi, good sending unit, oil level ok now what ?
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Old 10-22-2010, 10:16 PM
MBB MBB is offline
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Default Re: onan 6.5 NHEFA wont stay running

Is there an inline fuse. If so check that first.
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Old 10-23-2010, 12:29 AM
bbuchorn bbuchorn is offline
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Default Re: onan 6.5 NHEFA wont stay running

I have one also that I am waiting on a new control board for . The main things to look at. 1 check the 5 amp slow blow fuse on your control board and make sure it is ok. If you have to jump the coil circuit to run the spark and the fuel pump, and the fuse is ok. odds are that you have a bad control card. you can get the replacement one from Flight Systems on Ebay for 129.00. Another place to look is the plugs on the control card. sometimes the contact pins can get dirty, losing contact. Having to hold the button down to keep it running is a sign of no power generation. check your slip rings and brushes for good contact.
If you don't have the manuals please post your e-mail where you can receive large files and you may just find a very informative surprise in your inbox . the manuals have a good troubleshooting section, and will help you a lot.
As for the heavy surging, sounds like a dirty carb with a plugged up idle circuit.
I had to clean mine 3 times before I finally got it to run right. Make sure you have a good fuel filter in your system. Good luck with it. I is a good unit. BB
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Old 10-23-2010, 06:12 AM
Gunny Gunny is offline
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Default Re: onan 6.5 NHEFA wont stay running

Suggest laying hands on the service manual and do the trouble shooting before throwing parts at it.

Not often that the cause of the problem you describe is the control board, much more likely would be a failure to make voltage. If it set up for a length of time, look for stuck brushes as a start.
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Old 10-23-2010, 11:40 AM
dr fusion dr fusion is offline
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Default Re: onan 6.5 NHEFA wont stay running

e-mail address is donaldtheduck@sbcglobal.net thanks
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Old 10-24-2010, 05:28 PM
Pete Spaco Pete Spaco is offline
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Default Re: Onan 6.5 NHEFA wont stay running

Others may correct me if I am wrong, but a good place to start is to look for DC voltage across the choke heater wires. I think it should be about 20 volts when the engine is running. If it is not even close, but not zero, then I'd start by cleaning the slip rings, after making certain that the brushes aren't hanging up or have bad connections.
As others have said, DO get the manual.

Pete Stanaitis
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Old 07-18-2013, 06:27 PM
JulieDunn JulieDunn is offline
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Default Re: onan 6.5 NHEFA wont stay running

I too am having the problem with the engine quitting when I release the start button on a 6.5nhefa. Brushes and slip rings good, oil pressure switch good. Could you send me the manual you mentioned?
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Old 07-18-2013, 08:37 PM
len k len k is offline
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Default Re: onan 6.5 NHEFA wont stay running

Dr Fusion..... your NHE is spec (version) E (the last letter of the model #)
I believe that one has an electronic AC voltage regulator, behind control board or below circuit breakers. If didn't run for 4 years the surface of the slip rings likely got oxidized a little making the contact resistance to the brushes high. That usually kills the electronic AC voltage regulator that supplies the rotor windings thru the brushes. So the stator windings don't make AC. Without AC the control board will shut engine down when you release start button. BUT before you assuming you need parts, do this test.

Testing... with Ac regulator disconnected, engine off, measure resistance of rotor thru the brushes. should be 20-25 ohms plus 1-2 ohms for the brushes. If high clean with scotchbrite pad, till you get above ohms. Can't tell by looking have to measure. All way around !! Hook up regulator and start engine, if you're lucky it'll make AC.
Also check that brushes are not sticking in holder.

Tell us what you find, there's another test to do, before you buy parts.

JulieDunn ..... would be glad to help you. It would help both of us if you could post a new thread. It gets messy/confusing talking to 2 people in one thread. Also give full model and serial # , (they made several versions)

Dr Fusion..... heavy surging, sure sounds like carb needs a cleaning. They get gummy/dirty inside. I have a similar gen , had same surging, took carb apart and mechanically cleaned everything. Purred like a cat afterwards.
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