Onan 6.5 NHE

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newcple55

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Joined
Oct 26, 2005
Posts
7
The Onan gen set will start fine and as soon as I release the start switch is dies. I thought I had read something in here about this but can not find it now. Any ideas or direction to go would be appreciated. Thanks
 

Bob Zambenini

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Mar 4, 2005
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Orange County California
newcple55 said:
The Onan gen set will start fine and as soon as I release the start switch is dies. I thought I had read something in here about this but can not find it now. Any ideas or direction to go would be appreciated. Thanks

That woiuld be the case if your chassis batteries are low. At least on my QD Onan it will not run without chassis battery power although when it starts you would think that as it is producing power and it would keep running.

Bob
 

newcple55

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Oct 26, 2005
Posts
7
The oil level is fine, checked that.
Bob, when you were talking about chassis battery power, would your genset die as soon as you released starter switch?
The 2 house batteries were worn out so I took 1 deep cycle from the boat and put it in and am using that, it has plenty of power but is only 1 battery instead of 2 but I dont think they should matter, but you never know.
Thanks
 

John From Detroit

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Davison Michigan
newcple55 said:
The oil level is fine, checked that.
Bob, when you were talking about chassis battery power, would your genset die as soon as you released starter switch?
The 2 house batteries were worn out so I took 1 deep cycle from the boat and put it in and am using that, it has plenty of power but is only 1 battery instead of 2 but I dont think they should matter, but you never know.
Thanks

Yes, I have seen it where there was not enough enegery in the house batteries to start and maintain a generator, the igintion system in Onan generators is battery operated... .Once the transfer switch kicked in and applied generator power to the power converter (Which charges the batteries) the generator held.

There are other issues too,,, I don't know the age of your generator and in truth don't know if it has this type of system but I do recall some years ago helping a gentelman who had the same problem with his motor home.

It would start, but soon as he let loose the switch, it stopped running.

Turns out in his case there was a device called a "Ballast Resistor" in the ignition system, this is there to help prevent the points from burning up quickly on 12 volt Ignition systems, however it is bypassed during starting so as to give you a hotter spark.. His was bad,, The previous owner knew it was bad,  How do I know this? Spare ballast resistor in the glove box, that's how.

Fortunatly for him, I'm old enough to remember those.  They almost NEVER fail, but the key word is ALMOST.
 

Bob Zambenini

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Mar 4, 2005
Posts
270
Location
Orange County California
newcple55 said:
Bob, when you were talking about chassis battery power, would your genset die as soon as you released starter switch?
The 2 house batteries were worn out so I took 1 deep cycle from the boat and put it in and am using that, it has plenty of power but is only 1 battery instead of 2 but I dont think they should matter, but you never know.
Thanks

Most Onan generators start on Chassis Batteries so I don't think house batteries are a factor. But if my Onan does not have constant battery power it will stop when you release the start switch. Also they  shutdown if either the coolant or oil level is low. I know because my coolant got low and it shutdown.  Was not very low but low enough!!!

Bob
 

Ned

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The Onan generators will flash a code in the switch light to tell of any failures.  These codes are defined in the manual and, I think, on the external switch plate.
 

newcple55

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Oct 26, 2005
Posts
7
Thanks for all the ideas, this is a fairly old genset and does not have the flashing codes and it is air cooled so no coolant and oil is fine, but the ballast resistor sounds like it is worth looking into. Let me see what I can find, hey I might even have a spare somewhere. Ha
Thanks
 

Shayne

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Jan 22, 2006
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4,324
I had a similar problems couple of years ago and replaced everything that had been suggested and then some.  Even had the fuel tank removed flushed and sealed.  Come to find out the 12 inch rubber fuel line between the 2 steel lines was colapsing and shutting down the gen..  Replaced that and no problems since.    Good luck
 

gensetbill

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May 3, 2006
Posts
17
ok here is the scoop  onan nhe emerald has three reasons usually that it will quit after the release of the start switch. one is the low oil sensor. if you have sufficient oil in the genset hen you need to find the lead for the sensor and disconnect it on the sensor side and test the switch. the most common reason that the emerald shuts off is tat there is no voltage going to the ac windings, to make a older onan to run and stay runing you need a series of interlocks working ...oil pressure,fuel pump,spark,and the MAIN one that everyone misses the ability to generate power... in the start mode the interlocks are started up since it will run they are working... now the kicker when the start is released a relay on the control board takes over and alows the unit to keep runing if relay doesn't latch unit dies as soon as start is released.. not knowing what model you have sorta working in the dark so you may have to look around a bit but all of the older onans are very simular and also require the same parameters now the ability to generate power.. look at the back of the generater unit and on the back on the top is a plate held on by 2 screws if you remove one of the screws and loosen the other the plate will slide away revealing the brushes .. the brushs must be free a little pull and release and they should spring back into contact with communator and the comunator should be clean and shine if not use some real fine emery cloth and remove the brushes and clean the communator ... a small voltage must be generated by this guy to turn on the field windings to generate power if not the final interlock is not made and the relay will not latch and unit will die when start is released the third reason is a faulty start switch... good luck!
 

John From Detroit

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Apr 12, 2005
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Location
Davison Michigan
I'm reading my new FMCA magazine.  They have a letter writer who says he has an ONAN 6,500 watt generator
that starts, but stops soon as you release the start switch.  Wonders if it could be the ballast resistor

If you want I can copy the location of said resistor... That's what FMCA's experts thought it was.

Hummmm... Wonder if the letter writer is the original poster in this thread (not enough lead time)

Sure enough the RV-Doctor and I went to the same school of ignition systems, that's for sure
 

Shayne

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Jan 22, 2006
Posts
4,324
Just remember that if your fuel is down to 1/4 tank, it will react that what.  Also check for the fuel line from the Tank to the Genset, there is a rubber hose that has a tendency to collapse as units get age on them, even those of 5yrs.
 
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