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Ask Hank F. Your Own Question
Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 14489
Experience:  Certified on Onan and Generac generators
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I have the same problem.generator only runs with starter button depressed.replaced voltage

Customer Question

I have the same problem.generator only runs with starter button depressed.replaced voltage reg and control bd.Still does not run.also replaced oil pressure sw and new brushes.what's next?
Submitted: 1 year ago.
Category: Small Engine
Expert:  JohnF2015 replied 1 year ago.
Can you provide the model and serial number of your machine so that we can better assist you?
Customer: replied 1 year ago.
John.....model 7NHMFA26105G S/N. D973673639. Thanks
Expert:  JohnF2015 replied 1 year ago.
I have a list of possible problems that you can check:Engine Starts But Stops When Start Switch is ReleasedCheck oil level, make sure that oil is properly filled. You could have a bad oil sensor causing you problem.Check relay, you have a relay that has to operate in order to keep the engine running when the starter switch is released it locks to keep power going to the ignition, fuel pump, fuel solenoid on carburetor. If this relay is not working then as soon as you release the switch the engine will stop or die.Check output voltage from generator, if the generator is not producing voltage output this could cause the engine to not continue to run.If other checks prove to be okay, then the PC board it bad and will need to be replaced.
Customer: replied 1 year ago.
Oil and sw are ok.Where is the relay?I replaced the PC board and voltage regulator already.Voltage is present when button is pressed and works.I have new coach batteries like the other person's same problem that generator stops when button released.Could the problem be related to the new batteries in coach? Thanks
Expert:  JohnF2015 replied 1 year ago.
The batteries are most likely not the problem here. If they were the machine would most likely not even crank over when the starter switch is activated to start.The relay we are looking for is behind the start/stop switch panel, it is approximately 1" square, normally black in color, you can purchase a replacement at just about any automotive parts store.
Customer: replied 1 year ago.
Pulled relay it checkout Ok,but put in a new one anyway.NOTHING.What is next? thanks
Expert:  JohnF2015 replied 1 year ago.
Can you check to see if the genset is producing any voltage output when it does run?
Customer: replied 1 year ago.
Gen output is ok.It runs two AC units with no problem.......until you release the button. What is next? Thanks
Expert:  JohnF2015 replied 1 year ago.
The only other thing that you could have is a bad control board.
Customer: replied 1 year ago.
New control bd. and voltage reg. installed.nothing different. Thanks
Expert:  JohnF2015 replied 1 year ago.
I am sorry, we have gone all the way through the troubleshooting information that Onan offers for your machine and we have come to the end of their chart. You have tried everything that Onan suggests that could be a cause for your problem. I don't know where else to point you to. I am going to opt out of your question and see if one of the other experts may pick up on it and be able to help you.Again, I am sorry that I haven't been able to provide a solution for you.
Customer: replied 1 year ago.
Thanks,I appreciate your effort.Don't know what to try next......I'll have to give it more thought.
Expert:  Hank F. replied 1 year ago.
Hello!
My name is ***** ***** I am going to assist you with this.
There are actually a few things that will cause this genset to shut down like that.
First, unplug the remote from the genset. It is the black 8-pin connector located under the front of the control box. The wires will all be marked P2-X or J2-X.
Will the unit continue to run with the remote disconnected?
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Customer: replied 1 year ago.
Hank,unplugged the remote from the gen. NO change.Still stops when button is released.Could it be the governor module?What do I try next? thanks
Expert:  Hank F. replied 1 year ago.
Ok.
This unit has an electronic governor. I am not giong to lie - troubleshooting this is going to be a lesson in frustration. It is not easy at all.
The 5 things that will cause the governor controller to shut down are:
1. Battery voltage is lost to the governor controller.
2. Genset running too fast.
3. Oil pressure switch is activated.
4. Loss of ignition signal to governor controller.
5. Genset running too slow.
I know you said you tested it already, but you did not say how you tested it, so the first thing I need you to do is to unplug the wire from the low oil pressure switch, and tape it off so it can't touch ground.
See if the unit will run with that wire disconnected.
If not, the next thing I need you to do is to connect a frequency meter to the output leads of the genset, and measure the frequency while holding the start button to keep the engine running for a few seconds.
What frequency reading do you get?
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Customer: replied 1 year ago.
Hank,frequency meter used and voltage meter used and all readings are as they should.Everything in coach works....2 AC units,refrigerator,fans as long as the button is pushed.Oil pressure sw checked and replaced,old sw ok.Genset not running too fast or slow.With button in everything works as it should.Should we check the governor controller? Thanks
Expert:  Hank F. replied 1 year ago.
I need to know what the actual readings are. Sometimes I can see discrepancies that you may not even be aware of.
For the oil switch, there are actually 2 different switches available - that is why I gave you a specific test to do. I need to know.
I am very hesitant to say that your governor controller is bad. I have been working on Onan for 15 years, and have never seen one go bad.
At the 12-pin connector on the main control board, find the wire labeled J1-6 J6-A.
Leaving the plug connected to the board, back feed 12V into the back of the plug at that wire.
Will the engine stay running with the 12V applied?
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Customer: replied 1 year ago.
Taking readings and trying jumper today.Will get you the results. Thanks
Expert:  Hank F. replied 1 year ago.
Ok
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Customer: replied 1 year ago.
Hank,checked frequency with Holbut meter....... 59hz. Voltage meter Snap on 117-137v.Disconnected oil sw and taped it....no change.Connected jumper and gen. ran,but very FAST.Is this normal?What is next? Thanks
Expert:  Hank F. replied 1 year ago.
No, that is not normal. It should only have run at its rated speed.
Due to everything we have seen here, I have to say that I believe your governor controller may just be bad. I have never seen one go bad before.
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Customer: replied 1 year ago.
Hank,will try a new gov. Control.What took me to your web site was a Onan 7000 with the same problem on your cover page.Can you tell me what was its solution? Thanks
Expert:  Hank F. replied 1 year ago.
This is not my website, I am just an Expert here.
I have been here for 6 years now, and have helped thousands of customers. I have no idea which one you are talking about.
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Customer: replied 1 year ago.
Hank,you were the technician who solved the problem.http://www.justanswer.com/small-engine/48qpe-7k-onan-generator-motor-home-recently-changed.html#.VcNJYMqjqfo.mailto
I am not trying to give you a hard time,just trying to solve my problem.( john Hammond 21 Nov 2010. Resolved.) Is this info helpfully to locate this file? ThanksSent from my iPad
Expert:  Hank F. replied 1 year ago.
I have no idea what happened with that one. The guy quit responding to me. If you saw that question at all, you will have seen everything that transpired between us.
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