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stevebyrum1's avatar
stevebyrum1
Explorer
Mar 15, 2015

onan 7500 quiet Diesel

Hello all ,
I'm the new guy on the block. I recently purchase a 2002 Winnebago Journey with 5.9 Cummins engine. Only 25,00 miles on it and got a great deal on it.
Having said all that, It has a Onan HDKAJ 7500 quiet diesel generator that will not start. I have the service manual and have gone through what I think is all of the simple checks and still no start. Have changed fuel filter, primed pump, checked fuses, fuel flow test, fuel coolant and oil levels are correct.
Here is my question,
The person who owned this says generator was running a very short time prior to my purchase. I can't say as whether to believe him or not. I do however think he may have ran it out of fuel as it has a code 36 in the fault system. Fuel tank was low when purchased but full now. I have tried everything I can think of to clear this fault code but it is still there. Disconnected batteries, pressed stop button after retrieving code primed pump, etc.
If this code is still in the circuit board will keep fuel shut off at governor? I am getting no smoke at all, either blue or white, indicating no fuel flow. It cranks freely. I'm stumped....
Hopefully someone has had this before and can help.
Thanks in advance and I look forward to being a contributing member for this forum.

26 Replies

  • I have checked all the fuel lines.
    No blockage, no leaks, no dry rot, no inline filter.
    Fuel flow is good , so I know pump is working.
    I feel like if I could clear the code from the memory of the board it would run.
  • are you holding the start button long enough?
  • Fuel code - only way to find the problem is to "find the problem"

    How far up the line are you getting fuel flow?

    Blocked or criped fuel line/ filter.

    Lost prime?

    Getting air, sucking through a crack or bad gasket.

    Just keep going along the fuel line till the problem shows itself.

    BOL,
  • Some generators will not start/run if the main coach fuel tank is less than 1/3 full. This is an arbitrary fuel level as it varies with each RV. Make sure that your fuel tank is full and then check the fuel filters going to the generator.
  • if you fuel tank is low than it won't supply the genny with fuel. how much fuel is in the tank?