Onan Marquis Gold 7000

voltdr · 06-22-2015, 10:43 PM

It's unusual because it would restart immediately after shutting down. I even put a fan blowing on the genset but that didn't seem to help. I replaced the fuel filter and the generator ran better the next day. I'm going to pull it out and check the plugs and make sure there aren't any obstructions restricting the air flow.
Thanks for all of the suggestions and help.
Dan

voltdr · 06-22-2015, 10:59 PM

Sean,
I read your link. I have suspected that could become a problem. When I put a fan on it I try to place it so it blows the exhaust away from the inlet. I am going to fabricate a duct to deflect the exhaust away from the air intake.
Thanks for the help.
Dan

voltdr · 07-04-2015, 03:12 PM

Rich,
I have replaced both fuel filters, checked the screen for obstructions (none). Installed a deflector to direct the hot air away from the genset. Ran generator for about 2.5 hours with both A/Cs on. Shut off but gave me a 36 code this time.
Dan

voltdr · 07-04-2015, 04:59 PM

After reading the Onan manual for code 36, It said to check the fuel supply and also the air filter. I put in a new air filter and it seems to be running good now. I'm going to let it run for awhile longer.

Rich Biebel · 07-04-2015, 05:35 PM

Quote:

Originally Posted by voltdr

After reading the Onan manual for code 36, It said to check the fuel supply and also the air filter. I put in a new air filter and it seems to be running good now. I'm going to let it run for awhile longer.

It is definitely not the air filter.

Crimp the fuel line going to the filter so no fuel can get to the pump.

Let it run......Observe how it shuts off......

Read the code...it will be a 36...

If that is similar to how your machine quits...it is the pump.

I have been working on these machines for close to 15 years....

I know them as well as anyone.....and know just about every scenario of failures....

I did learn a new one this week.......

voltdr · 07-04-2015, 05:36 PM

It shut down again. This time it is a code 41.
GENERATOR ROTOR FAULT—CODE NO. 41
(Controller unable to sense field or output voltage)
Restarted and ran for about 15 seconds and gave the code 36 again.
Is that a controller issue or generator issue?
Dan

voltdr · 07-04-2015, 05:44 PM

Thanks for the info Rich. I will try the fuel line crimp and see how it shuts down. I agree about the deflector. This genset has run for 2000 hrs without one, why would that be a problem now. Might have to bite the "controller" bullet. Where is the controller located? Is it behind the stop/start panel?
Dan

voltdr · 07-04-2015, 05:53 PM

Rich,
After crimping the fuel line and observing how it shuts down, it's definitely different than how it has been shutting down. It shuts down abruptly when running normally. I will order a new controller. Mine is the HGJAB model. Is the controller the 300-5047 or 300-5374?
Thanks again.
Dan

Rich Biebel · 07-04-2015, 05:53 PM

The ECU is mounted behind the start/stop switch in a second section.

You have to remove the battery cable....remove that front switch box section. 1 10mm bolt to remove it.

3 10mm bolts hold the rear box with ECU inside.
2 bolts forward.....1 bolt in the rear....behind the box and down...
1 connector with a snap lock disconnects the ECU from the wiring harness......Pull it and examine the pins carefully for any that look discolored.....might be your problem but probably not...

ECU is held in that rear box with 2 screws......slide right out....
Heat sink on one side gets some air from the machine when it runs...

2000 hrs......is well more than enough to have this problem.....

Make sure the brushes are good if you did not check them....they also fail and cause odd shutdown faults.....easy to check...

Look at the upper area of the generator end....behind the switch area.....
2 wires going into a holder....one 10mm bolt......
Brushes are there....remove bolt....slide brush rig out.....brushes are about an inch long when new.....If one is bad it will cause the surface it rises on to be in bad shape.....sandpaper on a wooden stick will clean it up if needed.....they car copper slip rings....
Brushes are easy to get.....#212-1303 and probably also available from Parts for Techs...

Rich Biebel · 07-04-2015, 05:26 PM

Code 36 is a common one. Points to a loss of fuel and means the ECU did not shot it down.

The 2 items most likely to cause these shutdowns are the fuel pump and the ECU/Controller.

The fuel pump and solenoid at the base of the carbs fuel bowl are both energized on the same circuit.

If the engine shuts down abruptly when one occurs.....it IS the ECU. The voltage for the pump and carb solenoid is dropping out from the heat.
May or may not restart immediately or after sometime....Typical scenario.

If the engine starts running unstable and lopes up and down for a short time, it is the fuel pump. Carb still has fuel in the bowl and once pump quits, it takes a while to up the fuel remaining in the bowl.

The pumps are piston type and tend to fail and often do.

I change them both and just did for an RV customer a few weeks ago with this intermittant shutdown issue. His wife needed the AC and he had no interest in maybe this or maybe that......change both and lets get it done now.

There is no fix for this other than what I describe.

Cummins has 2 different heat deflectors now for a machine that will help direct the hot air away from the inlet side...but my experience with these machines says they are not going to fix units with intermittent shutdowns due to a bad ECU......

I have changed many ECU's on gas engine units and diesels.....all for the same issue...loss of power on the circuit that supplies the fuel pump....

It needs to be relayed in my opinion......

06-22-2015, 10:43 PM	#1
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: Onan Marquis Gold 7000 It's unusual because it would restart immediately after shutting down. I even put a fan blowing on the genset but that didn't seem to help. I replaced the fuel filter and the generator ran better the next day. I'm going to pull it out and check the plugs and make sure there aren't any obstructions restricting the air flow. Thanks for all of the suggestions and help. Dan

07-04-2015, 03:12 PM	#3
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: Onan Marquis Gold 7000 Rich, I have replaced both fuel filters, checked the screen for obstructions (none). Installed a deflector to direct the hot air away from the genset. Ran generator for about 2.5 hours with both A/Cs on. Shut off but gave me a 36 code this time. Dan Last edited by voltdr; 07-04-2015 at 03:20 PM.

07-04-2015, 04:59 PM	#4
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: Onan Marquis Gold 7000 After reading the Onan manual for code 36, It said to check the fuel supply and also the air filter. I put in a new air filter and it seems to be running good now. I'm going to let it run for awhile longer.

07-04-2015, 05:36 PM	#6
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: Onan Marquis Gold 7000 It shut down again. This time it is a code 41. GENERATOR ROTOR FAULT—CODE NO. 41 (Controller unable to sense field or output voltage) Restarted and ran for about 15 seconds and gave the code 36 again. Is that a controller issue or generator issue? Dan Last edited by voltdr; 07-04-2015 at 05:39 PM.

07-04-2015, 05:44 PM	#7
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: Onan Marquis Gold 7000 Thanks for the info Rich. I will try the fuel line crimp and see how it shuts down. I agree about the deflector. This genset has run for 2000 hrs without one, why would that be a problem now. Might have to bite the "controller" bullet. Where is the controller located? Is it behind the stop/start panel? Dan

06-22-2015, 10:59 PM	#2
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: Onan Marquis Gold 7000 Sean, I read your link. I have suspected that could become a problem. When I put a fan on it I try to place it so it blows the exhaust away from the inlet. I am going to fabricate a duct to deflect the exhaust away from the air intake. Thanks for the help. Dan

07-04-2015, 05:53 PM	#8
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: Onan Marquis Gold 7000 Rich, After crimping the fuel line and observing how it shuts down, it's definitely different than how it has been shutting down. It shuts down abruptly when running normally. I will order a new controller. Mine is the HGJAB model. Is the controller the 300-5047 or 300-5374? Thanks again. Dan Last edited by voltdr; 07-04-2015 at 05:57 PM.

07-04-2015, 05:53 PM	#9
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,320 Likes: 25 Liked 557 Times in 217 Posts	Re: Onan Marquis Gold 7000 The ECU is mounted behind the start/stop switch in a second section. You have to remove the battery cable....remove that front switch box section. 1 10mm bolt to remove it. 3 10mm bolts hold the rear box with ECU inside. 2 bolts forward.....1 bolt in the rear....behind the box and down... 1 connector with a snap lock disconnects the ECU from the wiring harness......Pull it and examine the pins carefully for any that look discolored.....might be your problem but probably not... ECU is held in that rear box with 2 screws......slide right out.... Heat sink on one side gets some air from the machine when it runs... 2000 hrs......is well more than enough to have this problem..... Make sure the brushes are good if you did not check them....they also fail and cause odd shutdown faults.....easy to check... Look at the upper area of the generator end....behind the switch area..... 2 wires going into a holder....one 10mm bolt...... Brushes are there....remove bolt....slide brush rig out.....brushes are about an inch long when new.....If one is bad it will cause the surface it rises on to be in bad shape.....sandpaper on a wooden stick will clean it up if needed.....they car copper slip rings.... Brushes are easy to get.....#212-1303 and probably also available from Parts for Techs... __________________ Rich Biebel S/C 1479 Stock 147R Last edited by Rich Biebel; 07-04-2015 at 05:59 PM.

07-04-2015, 05:26 PM	#10
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,320 Likes: 25 Liked 557 Times in 217 Posts	Re: Onan Marquis Gold 7000 Code 36 is a common one. Points to a loss of fuel and means the ECU did not shot it down. The 2 items most likely to cause these shutdowns are the fuel pump and the ECU/Controller. The fuel pump and solenoid at the base of the carbs fuel bowl are both energized on the same circuit. If the engine shuts down abruptly when one occurs.....it IS the ECU. The voltage for the pump and carb solenoid is dropping out from the heat. May or may not restart immediately or after sometime....Typical scenario. If the engine starts running unstable and lopes up and down for a short time, it is the fuel pump. Carb still has fuel in the bowl and once pump quits, it takes a while to up the fuel remaining in the bowl. The pumps are piston type and tend to fail and often do. I change them both and just did for an RV customer a few weeks ago with this intermittant shutdown issue. His wife needed the AC and he had no interest in maybe this or maybe that......change both and lets get it done now. There is no fix for this other than what I describe. Cummins has 2 different heat deflectors now for a machine that will help direct the hot air away from the inlet side...but my experience with these machines says they are not going to fix units with intermittent shutdowns due to a bad ECU...... I have changed many ECU's on gas engine units and diesels.....all for the same issue...loss of power on the circuit that supplies the fuel pump.... It needs to be relayed in my opinion...... __________________ Rich Biebel S/C 1479 Stock 147R