Generator issue - Stumped

[ZonComGMZ]

I have a Onan 5500 Marquis Gold Model 5.5HGJAB-1038.D. The generator has been working fine and has has about 500 hours on the Hobbs meter. The other day it was working fine and I shut it down as usual. The next day I tried to start it up and it started for 1 second and shut down. The same thing has been happening for the past few days whether I try to start it from the Remote or ont the Generator itself. Here is some of the troubleshooting I did. When it shuts off after a second the light on the start button blinks 3 times. When I hit STOP it then gives me the error code 47. I pulled the fuel hose to the carb and when it runs that 1 second it is getting fuel. When the code hits, the fuel flow stops although the generator will run if I spray starting fluid in the carb.

Any suggestions on what to do next?

[LJowdy]

It's an ignition code: Read this: My Onan Marquis 5500 Gold has a fault code 47. What do I do

[777 Driver]

I don't mean to be insulting, but, you have checked the fluid levels, right?

Here's a link to an Onan RV Generator Handbook: https://power.cummins.com/sites/defa.../F-1123-EN.pdf

Looks "generic", but, there are some troubleshooting suggestions starting on page 30.

God luck.

Take care,
Stu

[ZonComGMZ]

Originally Posted by 777 Driver

I don't mean to be insulting, but, you have checked the fluid levels, right?

Here's a link to an Onan RV Generator Handbook: https://power.cummins.com/sites/defa.../F-1123-EN.pdf

Looks "generic", but, there are some troubleshooting suggestions starting on page 30.

God luck.

Take care,
Stu

Fuel tank is FULL and Oil Level is topped off. That was my first thing to check.

[ZonComGMZ]

Originally Posted by LJowdy

It's an ignition code: Read this: My Onan Marquis 5500 Gold has a fault code 47. What do I do

I saw that but it looks like the problem was ever fully figured out. I was wondering if anyone had the same type of problem and what did they do to fix it. Going to pull it apart and check all wiring tomorrow.

[pchuckie]

FAULT CODE 47
WARNING Some genset service procedures present hazards that can result in severe personal injury
or death. Only trained and experienced persons with knowledge of fuels, electricity, and machinery
hazards should perform genset service. See Safety Precautions.
Logic:
HGJAB, C – No ignition signal at P1–15 for 1 continuous second
HGJAA – No ignition signal at P1–5 for 1 continuous second
HGJAD, E, F prior to 2004 – No ignition signal at P1–5 for 1 continuous second
HGJAD, E, F after 2004 in Engine Run Only mode only – No ignition signal at P1–5 for continuous second
Possible Causes: Wire connections, windings, ignition system, generator drive system
Diagnosis & Repair:
1. Verify that Last Fault is FC 47: Yes, continue diagnosis; No, troubleshoot actual last fault.
2. Alternating FC 47 and FC 37: Magneto gap too wide: reset magneto gap, retest.
3. Test Magnetos
A. Disconnect Connector P1.
B. Connect positive(+) meter lead to chassis ground.
C. HGJAA, D, E, F – Measure continuity to negative lead at pin P1–4 and P1–5: replace magnetos as
necessary.
D. HGJAB, C – Measure continuity to negative lead at pin P1–15 and P1–20: replace magnetos as nec-
essary.
4. HGJAD only – Run genset in Engine Run Only and externally excite field with 12 VDC or 24 VDC and
measure main and quadrature winding AC output.
5. Non EFI only – If the genset will not stay running measure genset frequency, quadrature winding and
main winding voltages using Break-Out Tool 420–0603 and Instruction Sheet R1098.
6. Measure AC frequency while changing engine rpm to determine if frequency response matches engine
rpm response: repair damaged generator drive system as necessary.
7. Measure field, quadrature and main winding resistance: clean slip rings, replace brushes, repair harness
and replace rotor or stator as necessary.
8. Measure field, quadrature and main winding resistance to ground: clean slip rings, replace brushes, re-
pair harness and replace rotor or stator as necessary.
9. Measure field, quadrature and main winding resistance to each other: clean slip rings, replace brushes,
repair harness and replace rotor or stator as necessary.
10. Check brush alignment per PSB-682a.
11. Verify that spark plug cables are secure on spark plugs: reconnect or replace as necessary.
12. Inspect ignition kill leads in harness and at connector P1: repair or replace lead, terminal or pins as neces-
sary.
13. Measure spark plug gap: set gap or replace spark plugs as necessary.
14. Verify ignition spark condition.
15. Inspect spark plug lead, kill lead terminal at magneto and measure magneto air gap: replace terminals,
set gap or replace magnetos as necessary.
16. Dealers contact Distributor for technical support, Distributors contact factory for technical support.

[pchuckie]

The service manual is readily available for download 983-0501d is the number of the book. For step 5 I don't recall for sure but I think you could back probe the connector to take those measurements.

[ZonComGMZ]

Originally Posted by pchuckie

The service manual is readily available for download 983-0501d is the number of the book. For step 5 I don't recall for sure but I think you could back probe the connector to take those measurements.

I will give this a try tomorrow. Thanks.

[DAN L]

ZomComGMZ,
I have a Genny similar to yours. It had about 400 hours on it.
It would run sometimes for a minute, sometimes for 30 min or so.
From the codes it looked like I had brush or slip ring problems.
I bought a slip ring cleaning tool from flight systems and cleaned the slip rings.
Still had problems.
One day when it quit running on a very hot day with the basement ac on, I stopped in a wide spot in the road and disconnected the oil pressure switch.
Problem solved. I've been running with the oil pressure switch pigtail tied back for over 2 years now. Imho Onan wants too many $ for the switch.
I just check the oil every time before starting the Genny.
Removing the connector from the oil pressure switch is an easy trouble shooting technique and it just may work for you as it did for me.

[alank]

By DAN L: Imho Onan wants too many $ for the switch.

I'm with that opinion. I had some trouble with my carb possibly because I let it set too long. Onan wanted $300 for a carb, which is about right, I have the same Nikki carb on my lawn mower and one of them was $300. I can take the generator carb off, take it apart, clean it, put it back together and on in about 30 min. Onan wanted $400 just to put new carb on, that was their fee. $700 for a new carb installed, take it or leave it.
I left it and cleaned the carb, runs fine now.

[ZonComGMZ]

Originally Posted by alank

By DAN L: Imho Onan wants too many $ for the switch.

I'm with that opinion. I had some trouble with my carb possibly because I let it set too long. Onan wanted $300 for a carb, which is about right, I have the same Nikki carb on my lawn mower and one of them was $300. I can take the generator carb off, take it apart, clean it, put it back together and on in about 30 min. Onan wanted $400 just to put new carb on, that was their fee. $700 for a new carb installed, take it or leave it.
I left it and cleaned the carb, runs fine now.

Carb is clean. No varnish from sitting around. Had to take off a carb on my last RV because the previous owner let it sit and not exercise the genny monthly.

[mojoracing]

I would try the oil pressure switch as well. That is exactly how a gen acts when it is low on oil so perhaps it is your switch. Another way to test it although not exact is when it starts to die, press the start switch for just a second. Do not hold it in, just press it. If it picks back up speed and runs for another couple seconds each time you do this, it usually is a low oil pressure issue. By the way, if you push it enough times (when oil level is actually low but not too low) the system can build enough pressure to stay running. I don't recommend doing this, but in a pinch while boondocking, it might get ya through when you forgot to bring extra oil. Oh the things you discover after working on these darn things for so many years LOL.

[ZonComGMZ]

Took it to a RV mechanic. He couldn't figure it out. He thought it was a carb issue. I took the carb off and cleaned it. No varnish anywhere. Looked clean but cleaned it anyway and blew out jets. Here is what else I notice. It runs for a second. When I press PRIME I see the fuel come out of the fuel line so I know the fuel pump is working. When I run the genny it runs for a second but after that it will shut off the solenoid in the carb and cut voltage to the fuel pump. It will still run if I spray carb cleaner in the throttle body. It stopped giving me code 47 but once it gave me code 36. Most times it doesn't give a code and just stops after a second. There is still a bit of fuel in the carb after it shuts the solenoid and shuts off the fuel pump also.

I was also able to have it run with the oil pressure switch, solenoid and vacuum switch disconnected and the carb off the engine by spraying carb cleaner directly into the manifold. This leads me to think it isn't an engine problem but something else such as a sensor, computer etc...

Any other suggestions?

[RolandRock]

First off - Do you have a multi meter? If so you can remove the cover from the electronics box and troubleshoot the entire ignition system with it. The sensors provide info from different parts of the unit to the run board. If any are tripped it will shut down after a couple of seconds of run time. The slip rings need to be cleaned occasionally, if your brushes have more than 30 ohms resistance between them , the unit will shut down. Are the brushes worn? Replace them. Get the tool listed above and clean your slip rings. This is necessary maintenance after 400 hours.