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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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Hank, I have an onan HGJAB LP generator that kills under load.

Customer Question

Hank, I have an onan HGJAB LP generator that kills under load. I checked the fuel water column to make sure it was getting the proper amount of fuel (11 wc), but if the generator gets more than about 2000 watts it kills. Any ideas?
Submitted: 1 year ago.
Category: Small Engine
Expert:  Hank F. replied 1 year ago.

Hello!
My name is ***** ***** I am going to assist you with this.

What is the full model number of the genset, exactly as it is written on the data label?

What fault code is the genset showing?

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Customer: replied 1 year ago.
Not sure about a fault code, but the model number is ***** I also just recently replaced both magnitos as one of the spark plugs had no spark.
Customer: replied 1 year ago.
and the spark plugs....
Expert:  Hank F. replied 1 year ago.

I would need the fault code to know where to start looking.

But just from what you are describing, it sounds like you have a bad demand regulator, and it is not allowing the proper volume of gas to get to the engine.

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Customer: replied 1 year ago.
I also tried to manually run the governor as the generator was killing, but couldnt keep it running under load. if I turned off the breakers as it was dying it would seem to run properly. how do I get the fault codes? I seem to remember it flashing 3 times when it killed, but I'd have to run it again to verify.
Expert:  Hank F. replied 1 year ago.

While it is flashing the 3 times, press the STOP button 1 time.

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Customer: replied 1 year ago.
I do it the morning and respond then.
Expert:  Hank F. replied 1 year ago.

Ok

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Customer: replied 1 year ago.

Hank, I got a 13.

Expert:  Hank F. replied 1 year ago.

Code 13 on this unit is Under Voltage.

There are many things that can be causing this - bad brushes, bad slip rings, bad rotor or stator windings, bad controller, bad drive system, or a fuel supply issue.

What you need to do right now is to get this unit connected to a load bank, to obtain accurate voltage and frequency readings under varying loads to determine where the problem actually is.

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Customer: replied 1 year ago.
Hank, the unit is under voltage because the motor is dogged down and running slow by being starved of fuel. I feel like you were right when you suggested that the demand regulator is faulty. Are there any fuel filters on an LP generator?
Expert:  Hank F. replied 1 year ago.

If the engine is noticeably slowing down, then yes, it is most likely a fuel issue - but it is still good to have a load test done.

There is no fuel filter on an LP unit - just the piping and regulators.

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Customer: replied 1 year ago.
Can you confirm the Onan part number for the regulator?
Expert:  Hank F. replied 1 year ago.
(###) ###-####/p>

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