QD8000 - Code 36

[f15epilot]

Posted this in the Class A forum. Thinking I’m more likely to get responses here, faster. Looking for some help.

I have a QD8000 in my Travel Supreme ME. It hit 1069hrs and began tripping an overheat shutdown fault. Being due the 1000hr service, I ordered the parts along with a new temp sensor, followed the service manual and installed everything. I fired it up and it ran flawlessly for over an hour at half and full loads.

Then, heading out the next week, it died while sitting still under 50% load (one A/C) giving a Code 36. I tried multiple restarts, both with priming (as much as 45 seconds with light and fuel pump audible) or just hitting switch. I also tried setting the C/B off (no load), though that shouldn’t matter. The motor cranks, then starts and revs to the RPM (by sound) of the generator about 75% load, then immediately shuts off. I get a slight puff of diesel exhaust that’s black then silence.

Here are all the things I’ve done to date:
- Oil and coolant levels are norm (both changed at 1000hr service)
- New fuel pump and filter (AFTER the shutdowns started)
- Verified diesel fuel flow at filter and prime works
- And yes, checked coolant at filler and reservoir

I’ll pull the top and side covers, and dig into the unit next weekend starting with the governor. Looking for advice on what to check since Code 36 is pretty vague on causes. Would especially love to hear someone on here had this same issue and found a (hopefully simple) solution.

Thanks in advance

[Busskipper]

Originally Posted by f15epilot

Posted this in the Class A forum. Thinking I’m more likely to get responses here, faster. Looking for some help.

I have a QD8000 in my Travel Supreme ME. It hit 1069hrs and began tripping an overheat shutdown fault. Being due the 1000hr service, I ordered the parts along with a new temp sensor, followed the service manual and installed everything. I fired it up and it ran flawlessly for over an hour at half and full loads.

Then, heading out the next week, it died while sitting still under 50% load (one A/C) giving a Code 36. I tried multiple restarts, both with priming (as much as 45 seconds with light and fuel pump audible) or just hitting switch. I also tried setting the C/B off (no load), though that shouldn’t matter. The motor cranks, then starts and revs to the RPM (by sound) of the generator about 75% load, then immediately shuts off. I get a slight puff of diesel exhaust that’s black then silence.

Here are all the things I’ve done to date:
- Oil and coolant levels are norm (both changed at 1000hr service)
- New fuel pump and filter (AFTER the shutdowns started)
- Verified diesel fuel flow at filter and prime works
- And yes, checked coolant at filler and reservoir

I’ll pull the top and side covers, and dig into the unit next weekend starting with the governor. Looking for advice on what to check since Code 36 is pretty vague on causes. Would especially love to hear someone on here had this same issue and found a (hopefully simple) solution.

Thanks in advance

Items that i would check - Possible water in the fuel - just enough to slow it down for a bit - Fuel filter Gasket - could be leaking, from dirt or .... - Fuel line with a less than "Pin Hole" leak - just enough to slow the flow of fuel or cause it to slow down.

Those would/should be the main culprits - Wires might also be giving the genny bad reading - oil - temp - at this age most of the issues I've run across are in just plain old/worn out wires - or corroded connections.

That's all I've got.

Hope it's simple - Best of Luck,

[f15epilot]

Just an update on troubleshooting.

I pulled the front, top, right and back panels, and checked all connections. All were secure; cleaned and resecured those with any corrosion. No change.

I then pulled the cover off the governor. I checked the throttle shaft for smooth, unbound movement. It moved freely. Hitting start, that shaft moves to midrange but immediately drops to low/cutoff at ignition. I found that I could hold the shaft and the engine would run for about 30 seconds until the controller shutoff the motor giving an over speed fault 25.

I think the issue is the stator not producing any current to actually drive the governor. Though not certain, I thought I heard/smelled hints of the windings being shorted. I have the diagram for the stator and will check resistances tomorrow. Will also check the low idle setting.

[f15epilot]

Referring to the service manual, I measured the resistances on the stator leads. There are two-each black, red and white leads. Those equate to three leads (red/black/white) for each of two bridge circuits. After some trial and error, it was clear that one bridge is shorted. One set has 1.7ohms between legs and near infinite resistance to ground (the stator case); the other had 1.5ohms between legs but 1.2ohm to ground, I.e., shorted.

Using the service manual which, BTW, is the same for both the QD7500 and QD8000 HDKAK models, I pulled the stator. It’s not too difficult; just have to take your time and label wires as you go.

Now looking for prices on the stator, which is now sold as a set with the magnet coil.

[Milehghcty]

About 3 weeks ago I got a code 36 on the QD7500. Besides the fuel filter on the motor itself, I had another in-line filter located behind the generator. It's the same as any gas filter. Changed it and now the motor runs just fine. It was starving for fuel. You stated you already changed your filters and have fuel flow, so probably won't be the same problem. But you may want to check to see if you also have an in-line filter somewhere that is slowing your fuel flow. My generator pulls out and the in-line filter was located behind the generator located on the back wall in front of the fuel tank.

[f15epilot]

Discussed my stator resistances with a friend who used to wind stators and rotors today. He confirmed that a short to case/ground means that bridge insulation has likely melted, so the stator is bad. That means it would produce no current. Running the start sequence, that explains the code 36.

When you press the start, the controller energizes the governor moving it to mid-range. At 800 RPMs (see page 10-3 of service manual), it disengages the starter and switches on the inverter which then should apply voltage to the governor to maintain RPM (2300 for 1st minute decreasing to a 1600rpm idle after 2min). BUT, with no voltage from the stator, the inverter puts out no voltage to the governor. As soon as that start cycle power is removed, the zero voltage lets the governor rotate to the safety cutoff position. Since the controller didn’t command shutdown it registers a code 36.

I’m now looking for recommendations from anyone who has had their stator rewound. I found another thread where someone had it done in Cal, but didn’t give a name or price. Only Google hit is $875 + shipping; parts for techs has the new stator/rotor combo (comes as a set) for $985 delivered. Thought I’d explore options before dropping a grand.

Anyone have any experience getting their stator rewound?

[f15epilot]

So looking on-line, there were a half dozen or more places listing the Onan A053K355 stator-rotor assembly for sale at just over $1000 to $1250. From experience I’ve found it best to call as websites can be deceiving. All of them said the same thing: the assembly would have to be ordered from Onan, and the wait time is measured in months...about six and counting.

The stator is now on the way to Eurton Electric in Whittier, CA. They responded quickly with the best quote, and gave an estimate of two weeks turn around.

Side note...the stator, with several layers of bubble wrap, nicely fits into a USPS Large Flat Rate box and weighs 43lbs, so under the 70lb limit.

[Busskipper]

Originally Posted by f15epilot

So looking on-line, there were a half dozen or more places listing the Onan A053K355 stator-rotor assembly for sale at just over $1000 to $1250. From experience I’ve found it best to call as websites can be deceiving. All of them said the same thing: the assembly would have to be ordered from Onan, and the wait time is measured in months...about six and counting.

The stator is now on the way to Eurton Electric in Whittier, CA. They responded quickly with the best quote, and gave an estimate of two weeks turn around.

Side note...the stator, with several layers of bubble wrap, nicely fits into a USPS Large Flat Rate box and weighs 43lbs, so under the 70lb limit.

Richard Nixon's College - in Whittier - Thanks for getting Back and when you put it all together let us know how it goes.


Best of Luck,

[rocketwheels]

Keeping an eye on this, my onan just started acting this way. Will check the usual suspects this weekend, just hoping its an easy fix like a clogged second fuel filter in line

[f15epilot]

Hi all. OK...here is the update.

Got the stator back from Eurton right after the new year. The employee who does these re-winds was out with COVID 10-days before Christmas, so it was just a bit late. Any other time and it would have been a 2-week-turn. No worries there; wasn't working on it over the holidays, anyway. BTW...Eurton was SUPER easy with which to deal and I highly recommend them. My cost was $850 for the rewind plus shipping, which is just shy of $50 to NW-Florida.

As the title says, you really do not need any special tools for this job. All of the bolts that hold the top & sides on are 10mm, and you can get to all of them with a socket (or power drill/driver) except some on the bottom; those may require a 10mm wrench if behind the fuel line. Note the bottom ones only need be loosened as the sides slide 'up' out of slots.

In short, the process is:
1) Disconnect the battery and power leads (note, your transfer switch should de-energize the dual 110V leads...but I unplugged just to be sure)
2) Remove the top
3) Remove the 'front' which is the long panel on the same side as the coolant/oil caps and NOT the black/shorter end, which is actually the left side per the manual.
4) Remove the back (which is the other long side); you can leave the right side in place. That is the one with the fuel connectors and battery leads
5) Drain the coolant and remove the radiator
(LABEL ALL THE WIRES and remove them or disconnect them at this point. I put labels on each of the stator wires...there are six...red/white/black x 2)
6) Remove the inverter assembly (heavy forward unit); there are six T-30 screws on the side closest to the fan that attach to the bulkhead, a grounding T-30 screw, and two T-30s on the bottom on the top side of the intake screen. You do NOT need to remove the black/white wires above the grounding harness since that harness stays with the unit.
7) Remove the T-30 or 10mm bolt that holds the bulkhead to the base plate and rotate/bend that bulkhead slightly back to clear the fan. Since these are steel bolts and that is an aluminum baseplate, don't be surprised if that bolt sheers off. Mine did as Onan appeared to not use any anti-seize on ANY of the bolts in the base plate.
8) Remove the three 10mm bolts holding the fan to the rotor and holding the bulkhead clear, remove it. (Note: these are torqued to only 7 - 9 lb-ft)
9) Remove the four bolts holding the stator and gently slide it off the rotor. Note, the magnet will resist this a bit. Don't grind it on the rotor as you slide it off or you'll be replacing that, too!

A note on the stator. There are two sets of 3-wire induction coils. If you look carefully at the matching sets that go to the inverter, you'll see those labeled 1-1, 1-2, 1-3, 2-1, 2-2 and 2-3. When you get your stator back, it comes labeled with the leads in two groups: 1, 2, 3 and E1, E2 and E3. There were just bare leads with no spade connectors attached. Eurton gave me new male spade connectors, but those were not the right size. Fortunately, I had several that fit. Suggest getting these in advance.

Installation is the reverse of the above steps. Torque values are 7-9 lb-ft for the stator and fan bolts; the rest are specified in the Onan service manual (and are essentially snug). I took this opportunity to replace the insulation on the left (black panel with the switch and C/B) before reinstalling everything. And as mentioned earlier, I had just done the 1000hr service, replacing all the hoses. If you haven't done that and are close, now is the time since you have it all apart...just buy new band clamps as the ones on there are 'crimped' and single-use.

Labeling the wires made reassembly easier and faster. Onan does pretty much make the connectors on the inverter-to-controller fairly idiot-proof with similar-colored wires using opposite male/female connectors. Don't forget the small inductor coil that is on the output wire harness--it connects to two connectors that go into the inverter. There were two unused connectors that I am glad I labeled as otherwise I would have spent hours looking for somewhere to connect them.

After assembly, it fired up flawlessly and runs as good (and quieter thanks to the insulation) as before with no codes.

BL...this is NOT a task that requires anything more than patience, a few common tools, the service manual (available from lots of places), some 10mm socket/wrench (and driver to make it faster), and a Torx-30 driver. If you have any experience doing your own routine maintenance, this is not a hard task. Take pictures...label things...and be careful moving the stator and inverter (both are heavy).

PS...in the first picture, you might notice that black air hose at the bottom. That feeds air from the intake around to the inverter for cooling. There is NO need to disconnect or remove it. BUT...if you do remove that clamp that holds it to the air box, don't forget to re-tighten that clamp BEFORE putting the fan and inverter back into the unit. There is NO way to get to it to tighten that clamp unless you remove the fan...which requires removing the inverter...ask me how I know

[texasrs]

What a terrific write-up.


Ray