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Author Topic: Onan Marquis Gold 5500 Generator Just Quit  (Read 986 times)

Heli_av8tor

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Onan Marquis Gold 5500 Generator Just Quit
« on: January 18, 2018, 11:42:02 AM »
Genny had been running for about 10 minutes when it died. It will run on restarts until the start switch is released.

Checked oil level - OK

Error code blinks: 27

There is a 20 and 30 amp breaker on the genny. Neither were tripped.

However, if I turn off the 30 amp breaker it will start and run. It dies if I flip it on. I turned off the main breaker at the AC panel with no change.

Any ideas?

Tom
Tom & Theresa
2004 Pace Arrow 37C, Workhorse W22, 8.1 Vortec
2014 Honda CR-V Toad, Roadmaster -5 Base and tow bar
SMI Stay and Play Duo Brake system

kdbgoat

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #1 on: January 18, 2018, 11:50:13 AM »
Just guessing here-bad cable from genny to panel or ATS, or bad ATS?
I know you believe you understand what you think I said,
But I am not sure you realize what you heard is not what I meant


2016 Leprechaun 319DS

Heli_av8tor

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #2 on: January 18, 2018, 11:53:34 AM »
What is ATS?

Note that the breaker doesnít ďtripĒ as if overloaded.
Tom & Theresa
2004 Pace Arrow 37C, Workhorse W22, 8.1 Vortec
2014 Honda CR-V Toad, Roadmaster -5 Base and tow bar
SMI Stay and Play Duo Brake system

Lou Schneider

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #3 on: January 18, 2018, 12:30:00 PM »
Error Code 27 says the control board is not sensing voltage from the generator.  That along with low oil pressure are two conditions that will make the engine shut down after you release the start switch.

Sounds like dirty slip rings or worn brushes that are blocking the excitation current from reaching the armature.  Or a bad control board that likewise can't generate the required field current.

Note that dirty slip rings can increase the strain on the control board, leading to it's failure.

RV generators differ from the "usual" textbook model in that the field coils receiving the excitation current are on the armature and the output is taken from the stationary coils surrounding it.

With the 30 amp breaker off there's no load on the generator so the limited field current can let the voltage build normally, but the generator can't get enough excitation to maintain that voltage when a load is applied.

Flight Systems makes replacement regulator and control boards for Onan products, both the RV and commercial lines, and they have long offered free troubleshooting guides on their website.

They now have a good YouTube video on their website showing how to check the generator's internal condition using a multimeter.

If all that fails, you can also get free tech support by appointment.
« Last Edit: January 18, 2018, 01:09:57 PM by Lou Schneider »

Heli_av8tor

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #4 on: January 18, 2018, 01:09:36 PM »
Thanks Lou,

Brushes make sense and I need to figure out how to access them. The genny was under a fairly heavy load this morning when it died.

Iím not sure what increased load would be on genny when I close the 30 amp breaker. The A/C panel had all breakers off so I donít know what would be powered.

Armed with my meter and service manual Iíll head out soon to see what I can discover. Had to take a break to deal with a credit card fraud attempt. You know, when it rains...

Tom
Tom & Theresa
2004 Pace Arrow 37C, Workhorse W22, 8.1 Vortec
2014 Honda CR-V Toad, Roadmaster -5 Base and tow bar
SMI Stay and Play Duo Brake system

Lou Schneider

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #5 on: January 18, 2018, 01:11:10 PM »
The load could be anything, including the load of the transfer switch coil itself if there's a bad restriction.  But dying while under load suggests a regulator failure, perhaps due to trying to force high current through a bad field connection.

Check out the videos on the Flight Systems website, they're simple but really informative.
« Last Edit: January 18, 2018, 01:27:27 PM by Lou Schneider »

Heli_av8tor

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #6 on: January 18, 2018, 03:31:39 PM »
They donít make it easy to get to stuff. The book calls for 29.x ohms on the stator brushes. I get30.4 which I deem ok. Pulled the brush away and they look good and within specs for length. The slip rings look good too. I would liked to clean them but all I had was a pencil eraser. It didnít do much. Pretty sure allís well there.

Will check out the videos next.
Tom & Theresa
2004 Pace Arrow 37C, Workhorse W22, 8.1 Vortec
2014 Honda CR-V Toad, Roadmaster -5 Base and tow bar
SMI Stay and Play Duo Brake system

Bill N

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #7 on: January 18, 2018, 04:02:08 PM »
They donít make it easy to get to stuff. The book calls for 29.x ohms on the stator brushes. I get30.4 which I deem ok. Pulled the brush away and they look good and within specs for length. The slip rings look good too. I would liked to clean them but all I had was a pencil eraser. It didnít do much. Pretty sure allís well there.

Will check out the videos next.

Tom, have you checked the very simple thing first - are you below 1/4 tank on fuel?  It shuts down at that point but I don't know if it will even start so just asking the question.
Bill
Bill & Joan N in Missouri
USAF (Ret - 1961-1981)
2002 Winnebago Adventurer 35U
Workhorse W22, 8.1L Chevy V8
2013 Chevy Sonic Toad
Furbearers:  Heidi-17(Forever), Cats: Grace-11 & Squeak-6, Winnie the ShihTzu - 16 mos

Heli_av8tor

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #8 on: January 18, 2018, 05:55:06 PM »
Thanks for the thought. Iím aware of that and over 3/4ths tank.

Looking more and more like the combo control / regulator board for (gulp) $329 from Flight Systems for aftermarket part.
Tom & Theresa
2004 Pace Arrow 37C, Workhorse W22, 8.1 Vortec
2014 Honda CR-V Toad, Roadmaster -5 Base and tow bar
SMI Stay and Play Duo Brake system

Bill N

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #9 on: January 19, 2018, 07:14:36 AM »
Thanks for the thought. Iím aware of that and over 3/4ths tank.

Looking more and more like the combo control / regulator board for (gulp) $329 from Flight Systems for aftermarket part.

Gulp is right but that would not even buy a single battery for my portable oxygen concentrator - $399.  But you and I have the same generator so now you have me sweating that out too..................lol
Bill & Joan N in Missouri
USAF (Ret - 1961-1981)
2002 Winnebago Adventurer 35U
Workhorse W22, 8.1L Chevy V8
2013 Chevy Sonic Toad
Furbearers:  Heidi-17(Forever), Cats: Grace-11 & Squeak-6, Winnie the ShihTzu - 16 mos

John From Detroit

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #10 on: January 19, 2018, 09:15:46 AM »
Per my PDF copy of the manual
PMA SENSE LOST FAULTóCODE NO. 27
(Controller unable to sense PMA frequency)

Not voltage but frequency... Voltage is a different code.
possible causes: Bad control board. Temps below -40 (or some other arbutary number darn close to -40 and since it ran 10 mniutes I doubt that)  bad brushes/slip rings. bad generator (other issue) loose wire.

Of all those my money is on the control board.
Nothing adds excitement like something that is none of your business
My Home is where I park it.

Heli_av8tor

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #11 on: January 19, 2018, 02:38:34 PM »
Thanks John for looking up the error code. For some reason my manual shows it differently. (See Picture)

I too am betting on the control board but keep thinking of things to check before dropping the cash.

I'm puzzled by the genny running if I don't turn on the 30A breaker. The sense line connects to the genny side of the breaker. Turning the breaker on doesn't trip it or give any indication of a short. Shore power works ok. I'm going to load thee genny with the MH wiring disconnected to see if it still quits.

Tom & Theresa
2004 Pace Arrow 37C, Workhorse W22, 8.1 Vortec
2014 Honda CR-V Toad, Roadmaster -5 Base and tow bar
SMI Stay and Play Duo Brake system

Lou Schneider

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #12 on: January 19, 2018, 03:02:27 PM »
They donít make it easy to get to stuff. The book calls for 29.x ohms on the stator brushes. I get30.4 which I deem ok. Pulled the brush away and they look good and within specs for length. The slip rings look good too. I would liked to clean them but all I had was a pencil eraser. It didnít do much. Pretty sure allís well there.

Will check out the videos next.

After checking the field winding and slip ring resistance at the Molex plug, the video recommends cranking the generator and verifying the resistance stays constant as the armature rotates.

One failure mode is a "rolling short", where varnish has come off of the armature winding and gravity's pull only makes it short out at a specific point in the rotation. This will be shown by the resistance dipping to a very low value as the armature rotates.

The resistance jumping high points to a bad spot on the slip rings or brushes.
« Last Edit: January 19, 2018, 03:09:09 PM by Lou Schneider »

John From Detroit

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #13 on: January 19, 2018, 04:16:36 PM »
Be it voltage or frequency (By the way My Generator is the same model).

The suspect list is the same.
Nothing adds excitement like something that is none of your business
My Home is where I park it.

Heli_av8tor

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #14 on: January 19, 2018, 07:35:01 PM »
 :) Problem found!  :)

Thanks everyone for your input.

I did the crank test and found the field resistance steady at 29.3 ohms.

It kept bothering me that with the 30A breaker off the genny would run, but instantly die when turning the breaker on.

I disconnected the wire to the motorhome from the breaker and alligator-clipped a 100 W trouble light to the terminal. When I started the genny and turned on the breaker it kept running and illuminated the lamp. Hmmmm.

The AC cable from the genny goes to a four-square junction box and then to the transfer switch. The transfer switch lives in a 5" cube attached to the back of the AC/DC load center which lives under the bathroom lavatory. It was a struggle to get it out. I had to unhook numerous wires.

Once access was gained the problem was obvious. The hot wire from the genny went to a connection block. The connection must not have been tight and overheated, melting the connecton block. This allowed the wire to touch the grounded mounting bracket.

It will take some time to put it all together but the fix will be free.  I can't help but wonder how many parts and hours a dealer would have thrown at it before finding the problem.

Tom
« Last Edit: January 19, 2018, 07:37:43 PM by Heli_av8tor »
Tom & Theresa
2004 Pace Arrow 37C, Workhorse W22, 8.1 Vortec
2014 Honda CR-V Toad, Roadmaster -5 Base and tow bar
SMI Stay and Play Duo Brake system

Bill N

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #15 on: January 20, 2018, 07:23:54 AM »
Great news Tom.  I am sure you are relieved to see it was a loose connection that caused the problem.  Now I won't be sweating quite so much.

Bill
Bill & Joan N in Missouri
USAF (Ret - 1961-1981)
2002 Winnebago Adventurer 35U
Workhorse W22, 8.1L Chevy V8
2013 Chevy Sonic Toad
Furbearers:  Heidi-17(Forever), Cats: Grace-11 & Squeak-6, Winnie the ShihTzu - 16 mos

Paul 1950

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #16 on: January 20, 2018, 09:10:12 AM »
Glad to see you figured it out.  Persistence pays!
Paul S   Iowa
2005 Winnebago Voyage 38J

garyb1st

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #17 on: January 20, 2018, 08:27:09 PM »
Glad you found the problem Tom.  If I have an issue, I'll look you up.   ;)
Gary B1st

2005 Pace Arrow 35G
2016 Jeep Wrangler

Heli_av8tor

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #18 on: January 20, 2018, 10:50:59 PM »
Anytime Gary.

Finally got all the wiring repaired and tucked away about an hour ago. While the main panel was out I couldnít run the generator that HueyPilotVN loaned me. Batteries had dropped to 47%. Hate that they went that low, but...

Hope my genny doesnít keep you up. Iíll kill it at ten. Iím sure itís not the sweet music to others that it is to me right now  :D
Tom & Theresa
2004 Pace Arrow 37C, Workhorse W22, 8.1 Vortec
2014 Honda CR-V Toad, Roadmaster -5 Base and tow bar
SMI Stay and Play Duo Brake system

Bill N

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #19 on: January 21, 2018, 06:24:15 AM »
Anytime Gary.

Finally got all the wiring repaired and tucked away about an hour ago. While the main panel was out I couldnít run the generator that HueyPilotVN loaned me. Batteries had dropped to 47%. Hate that they went that low, but...

Hope my genny doesnít keep you up. Iíll kill it at ten. Iím sure itís not the sweet music to others that it is to me right now  :D
Tom, a bit off topic but could you give me you thoughts on the CRV toad.  I know the past couple of years they have not made one that can be towed 4 down but the car has always interested me for a toad.  Our little Sonic is very nice and easy to tow but it the word 'little' describes it. The CRV looks to be quite a bit better.

Bill
Bill & Joan N in Missouri
USAF (Ret - 1961-1981)
2002 Winnebago Adventurer 35U
Workhorse W22, 8.1L Chevy V8
2013 Chevy Sonic Toad
Furbearers:  Heidi-17(Forever), Cats: Grace-11 & Squeak-6, Winnie the ShihTzu - 16 mos

kdbgoat

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #20 on: January 22, 2018, 07:29:49 AM »
:) Problem found!  :)

Thanks everyone for your input.

I did the crank test and found the field resistance steady at 29.3 ohms.

It kept bothering me that with the 30A breaker off the genny would run, but instantly die when turning the breaker on.

I disconnected the wire to the motorhome from the breaker and alligator-clipped a 100 W trouble light to the terminal. When I started the genny and turned on the breaker it kept running and illuminated the lamp. Hmmmm.

The AC cable from the genny goes to a four-square junction box and then to the transfer switch. The transfer switch lives in a 5" cube attached to the back of the AC/DC load center which lives under the bathroom lavatory. It was a struggle to get it out. I had to unhook numerous wires.

Once access was gained the problem was obvious. The hot wire from the genny went to a connection block. The connection must not have been tight and overheated, melting the connecton block. This allowed the wire to touch the grounded mounting bracket.

It will take some time to put it all together but the fix will be free.  I can't help but wonder how many parts and hours a dealer would have thrown at it before finding the problem.

Tom

"Told ya" ;D I get lucky on diagnosis once in a while.

Glad you found the problem and got it fixed.
I know you believe you understand what you think I said,
But I am not sure you realize what you heard is not what I meant


2016 Leprechaun 319DS

Heli_av8tor

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #21 on: January 22, 2018, 08:26:32 AM »
Yes you did. What threw me was that when closing the breaker there was no indication that there was a short. The genny controller shut it down before the breaker could react.
Iíve closed more than one breaker on a shorter circuit and heard the arc and breaker snap open. No such feedback on this.
Tom & Theresa
2004 Pace Arrow 37C, Workhorse W22, 8.1 Vortec
2014 Honda CR-V Toad, Roadmaster -5 Base and tow bar
SMI Stay and Play Duo Brake system

John From Detroit

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Re: Onan Marquis Gold 5500 Generator Just Quit
« Reply #22 on: January 22, 2018, 10:32:39 AM »
I agree that's a new one on me too, a short.. I'd have thought the breaker would well Break (the circuit that is) but I guess it has a bit of "Hang time" (most do)....

in another system I have a device that likes to blow fuses. So I switched to a breaker precisely due to that short delay.. And promptly blew the controller.. thankfully that was an eaxy no-cost fix (Just needed a bit of solder and a strand of scrap wire and of course about $150 Dollars worth of Terchniciasn timer.. but bering as I am the technician that weas $0.00) Works great now.

I now use the circuit breasker and a relay that can handle far more current. Last test was good.
Nothing adds excitement like something that is none of your business
My Home is where I park it.