Onan 5.5 HGJAB Marquis quit...

mowermech wrote:
Nice link, but this unit won't fit through the door opening. It appears it has to drop down and out. I would have to rent a jack to lower it and put it back.
At my age, I am not enamored with such projects anymore. Just laying on the ground working above my head makes me dizzy these days.
Once it was out and laying in front of me, I could fix it no problem.
Getting it out and back in though....

Take another look and isn't the lower bar of the basement compartment removable with a couple of bolts on each side. Obviously, I can't see it from here, but if not, you may be able to cut it out and then bolt it back, when done.
Also, don't even attempt to wrestle it to someplace else and just work on it right there on the ground, but you should have a platform under it of course and pretty much mandatory for using a floor jack.
A decent floor jack at harbor freight is worth the money and will pay for itself, by doing this one job.

I recommend the Cummins dealer.

I had problem with a Gold Marquis 7500 Onan and after three different mechanics and RV dealer cost me a $1,000.00 it still did not work.

Found a Cummins dealer and they removed and repaired it for around $900.00 Saved a good amount by joining the Cummins Power Club.

Pirate wrote:
Pushing around 1500 hours on mine. At what age/hours does one expect to replace the generator vs repair?

Probably never, but depends on what you have.
With our Onan Diesel and saving a rare catastrophic event, I don't think I'll live long enough. There's many running fine at 12,000 hours.
With our old gasoline 5.5 Generac, I'm not so sure, but still, a complete rebuild, would be better than buying a used one, as there are no new replacements for them. Nothing out there with the same power in such a compact size, either.

Pushing around 1500 hours on mine. At what age/hours does one expect to replace the generator vs repair?

mowermech wrote:
It appears the problem is the drive belt or the drive coupling, or both.
regardless, the rotor is not turning. The engine starts then dies, apparently because the control board is not sensing output voltage.
Has anybody encountered this problem?
What did it cost to get the genset removed, repaired, and reinstalled?
So far, the only place I have found to get the work done is the local Cummins/Onan dealer. They can't look at it until the 10th.
Luckily, I have a power/water pull-through site for our next trip.

Figure approx. $138/hr labor and about 2.5 - 3hrs total for in and out + whatever the problem might be with it. This assuming absolute honesty and no extras.
With over 1000 hours on the unit, they will want to replace the belt and hoses, no matter how new they look, so your call on that sort of thing.

have done that job many times...yes, the set must be removed from vehicle. The engine /gen assembly must be removed from base tray, turned up on back side, need some lifting equipment or couple of strong helpers. also need some pullers, as flywheel and gen pulley need to be pulled. Would recommend replacing tensioner assembly when belt replaced. It is possible that belt not broken, but rubber coupler hub
between flywheel and pulley is broken, and would be pretty much same repair procedure...regardless of which is broken, both should be replace while you have it apart. Parts are not very expensive, but is kind of labor intensive. be sure to have rotor bearings and brushes and slip rings on rotor serviced while it is apart.

I removed the brush holder and watched the rotor while cranking the engine. It did not move.
While I had the bottom cover off, I tried turning the generator cooling fan. It turned with only a slight drag.
There is no doubt in my mind that the generator is no longer firmly attached to the engine!

I pulled my onan 5500 out a year ago to replace the rotor unit has to be pulled out completely and disassembld how do you know the rotor is not turning

I had the bright idea that maybe the fan shroud was removable with the genset in place, so I parked the MH on the concrete driveway and removed the bolts in the cover. No joy, that does not give access to the belt.
So, I put it back.
Looking at the Illustrated Parts Breakdown, the generator baseplate IS the fan shroud. The generator will have to come out of the motorhome to change the belt and coupling. It looks like it will go to Cummins/onan after the Hamfest.

On my Onan Marquis 7000, the control board in in the black box where the external starter switch is mounted. The board is expensive, but not difficult to access in the genny bay.
BTW - I just changed the starter motor on my genny, and using a maintenance pit, the job was manageable.
I agree that the idea of dropping the tray and reinstalling makes me tired contemplating it!