Onan Emerald 3 Generator, no spark!

[ClydesdaleKevin]

Welp, while cleaning the solar panels today and checking my battery water levels, I decided to check the oil in the genny and fire it up to make sure it was ready to run in case we need it out in the desert.

I pushed the start button, and nada...the starter motor turns the engine over, and the fuel pump runs, but there is absolutely no spark going to the spark plugs.  It wouldn't even start up with brake cleaner.  I pulled the plug wire, put a bolt in the lead, and held it near a good ground, pushed the button, and no spark at all.

I can smell gas at the exhaust pipe, its just not firing.

What do you guys think?  Bad coil?  Could it be anything besides the coil?  Coils for these things are damn expensive (its got the cylindrical one with the two spark plug leads coming out of the top of it). 

The circuit board was replaced a couple of years ago with a dinosaur board, so its probably not that.  Its not the fuse either...checked it.

So what do you all think?  I'm guessing its the coil, but not sure, and don't want to shell out the cash for one if that is not the problem.  Any way to test the coil?

I know its getting plenty of battery juice!  It starts off the coach batteries (6 golf cart batteries).

I really doubt we'll need the genny at all while we boondock, not with my solar power system, but I really wanted it to be running as a back up, just in case.  My system is essentially untested, and the panels are flat mounted...again, I'm probably just a worry wart, but I'm an Eagle Scout...I like to be prepared!

Guess my new solar power system is going to get tested like crazy!  Trial by fire...

Anyhow, let me know if there is something else I should be looking at besides the coil. 

If this 3 week leg of the journey goes well boondocking, I might sell the Onan and get a small portable Honda as a backup...we haven't used the Onan at all since we did all the upgrades...less weight and more storage space is always good!

Thanks! 

Kev

[DaveVA78Chieftain]

In order to help I need to know specifically what model Onan you have.  There are different manuals with different electrical setups depending on Spec letter. So I need the model number to select the correct manual.  Should be something like 6.5NHEFA63753L.

Dave

[ClydesdaleKevin]

Its the 6.5NHE...L


Kev

[DaveVA78Chieftain]

Service manual for a 6.5NHE...L is 965-0528 which is available in our free manuals section.   Select Generator then scroll down the page to the NHE section.  Your Spec L unit uses electronic ignition instead of points. 

Section 7 describes the sequence of events for Start/Run/Stop.
Start of Troubleshooting process is on page 7-7 (pdf page 99) however your symptom starts on page 7-8 (pdf 100).   I would do test number 3 (power to coil) before I did test 1 (ignition circuit test).

Description of electronic ignition is on page  6-10 (pdf page 64).  Includes test procedures.  Ignition control module is hidden under the fan shroud.  B+ is applied to the coil from the control board.

Closest wiring diagram is Fig 8-4 on page 8-6 (pdf page 108)

Dave

[ClydesdaleKevin]

Thanks Dave!  I was looking through my RV binder, and it turns out I have all the original manuals on hardcopy  D:oH! .

I'll be troubleshooting it as far as I can when we get to Hot Wells dunes in a couple of days.  Hopefully my solar power system is up to the challenge, since we don't have a backup now...unless I want to start the engine and let it run at a high RPM for hours  ...not really an option...lol!

As always, just hoping for an easy answer like, "Yeah, that happened to mine, blue wire was loose..."  That sort of thing. One can always hope!

With my luck, it will be something expensive like the coil.  But at least I have the tools, the electrical knowhow, and the manuals!

Kev

[DaveVA78Chieftain]

Ignition circuit itself is simple.  Ignition module, coil, capacitor, plugs and wires.  As I said before, first  step is to see there is 12VDC at the coil when you depress start.

Dave

[DonD]

Maybe help here too; http://www.smokstak.com/forum/

[Oz]

What an incredible coincidence!  The exact same thing happened to me and after troubleshooting and replacing parts until I was blue in the face and empty in the wallet, I figured out what the problem was... the blue wire was loose..."




(Sorry but, somebody had to...)

[ClydesdaleKevin]

LMAO Mark!  And thanks Dave!  I'll run the diagnostics when we get settled in in camp tomorrow.


Kev

[ClydesdaleKevin]

My bad...turns out my genny is spec E...with points and condensor, not electronic ignition.  Same service manual though.

Complete model number:  6.5NHEFA26100E

Also turns out the manuals I have are simplified user and installation manuals, so thanks Dave for pointing me to the service manual!  It shows me how to test the coil, set the point gap, and even test the circuit board.  I'll be playing with it tomorrow.

Kev

[bluebird]

Kev, my old onan 4.0 BFA used to eat points and condensers. About 1 set a year, but I used it a lot, several starts a day at the track.  The last set I bought at our local onan dealer cost me 60 some bucks. I bought several sets off a guy on the bay for 16.00 each. It also used to burn off the wires where they go i the coil.

[ClydesdaleKevin]

Thanks Bluebird!  I'll check all that out, including the wires.  Points were replaced 2 years ago by the guy we used to have service our genny in NC every year, but he didn't show up this year.  So I'm doing it myself now, as with pretty much everything I have the tools for...lol!

I looked back on my receipts, and the points were definitely replaced 2 years ago...but no mention is made of the condenser on the receipt.  I'm going to static check the coil tomorrow or the next day (helping a friend out with solar tomorrow) with my ohm meter and see if I can eliminate it from the equation.  I'll also run the diagnostics with my Fluke on the circuit board, also replaced 2 years ago.

Funny thing about my manuals that came with the RV and the genny...they are hard copies, original print.  And yep, they have a very short troubleshooting section.  And at almost every point in the troubleshooting, it just says:  Contact your Onan dealer.

Guess they didn't want you working on it yourself!

The manual I downloaded from the member section tells me how to do it all!!!

Kev

[bluebird]

Yea, our onan dealer here in town is not much help either. They want the work, they won't tell you much. I had a book for my old onan, but don't remember where I bought it. Let it go with the Itasca. I also had a problem with the control board on it, I think it was a switching transistor. Had an electronics tech at work fix it for me. It'd start but shut off as soon as ya let off the button, but it was much older than yours. If you use the genny a lot I'll bet it's the points.

[DaveVA78Chieftain]

Good luck Kevin.  Hollar if you need something.  Given that it covers so many different versions, just make sure you are reading/using the right information in the manaual.

Dave

[ClydesdaleKevin]

Will do Dave!  Thanks!  I'll be tackling the troubleshooting tomorrow...spent most of the day exchanging war stories with the camp host...comparing solar notes and whatnot...and then spent the last couple of hours installing my old solar panel and charge controller on our friend Arlene's air conditioner.  Running the wires was a bit of challenge, but we only had to drill one hole, so that's good!  Its only a 65 watt Kyocera panel, with a Sunforce 7 amp charge controller, but its still better than the crappy Harbor Freight 45 watt setup she was using before...and if she uses both together she'll have 110 watts of solar...so its a step up and didn't cost her anything.  She only had 2 golf cart batteries so it should help quite a bit.

So far so good with our solar set up!  Thankfully we haven't had to use our genny.  We even fell asleep by accident last night with the TV still on and the inverter still drawing power.  Woke up to 12.4 volts, and even though it was partially overcast all day, the system still fully charged the battery bank by 4pm.  5 hours.  Not bad!

Kev

[ClydesdaleKevin]

So I took off the points cover and the points were pretty dirty...not pitted though, so I took a white business card and cleaned up the points.  Then I disconnected the wires going to the coil, and did an ohm test....+ and - tested right within specs, but the high voltage leads tested way lower than specs.  I reinstalled the wires, figuring that was it...bad coil.  And then hit the start button just for fun...and it started right up!   Hm?

So I've got spark again, even though the coil seems to be on its last legs, and the idiot mechanic didn't replace the condenser when he replaced the points...its still the original one, painted Onan green.  So a new coil and condenser are on the list of things I'll replace.

It ran great for around 5 minutes...and then stalled out like it wasn't getting enough gas.  I pulled the fuel line and the pump gives suction...so I sucked on the fuel line and got a mouth full of gas.  I checked for a fuel filter, but unless its built into the fuel pump, I couldn't find one...and I traced the fuel line right back to the gas tank.

So I hit the toggle switch installed a couple of years ago by my Onan mechanic that bypasses the circuit board and turns on the fuel pump, and she WANTED to start, but wouldn't quite start.  A fuel delivery problem?  Maybe the in the tank pump when it came loose knocked the pickup tube out of whack?  I was going to try to run a fuel line to a gas can to eliminate it out of the equation, when the starter stopped working.  Oi vey!

I smelt a bad smell, like electrical burning, and then the starter stopped starting.  The smell was coming from the control box that houses the circuit board and the starter solenoid, so it could be either one that died...dangit!  Not attributable to a low battery either...it starts off the coach batteries which were at 12.5 volts when I was working on it. 

The fuel tank is 3/4 full.

So now I have another problem that I'll have to fix when we get back to work for the season:  The starter or the solenoid, or possibly the circuit board.

And then once she'll turn over, I can continue the troubleshooting...if its not one thing its another!

Kev

[bluebird]

Don't condem that coil just yet Kev. Change the points, condenser, and plug wires first if they are original. My onan had a filter screen in the pump. If you got a mouth full of gas, then the pump should be able to pull the gas too.

Can you tell if the pump is running? I had to take mine apart and clean it several times, but it's been a long time and I don't remember what I found wrong with it.

Does yours have a starter or does it use the windings in the genny to start? If it uses the windings, it will pull a lot of amps. I had to clean the brush holders one time to get mine to start.

I know onans are supposed to be great gennys but the 2 BFAs that I have owned needed a lot of maintenance to keep them running. I now have a Generac and have had pretty good luck so far with it. I did have a regulator replaced this summer, but it is pretty old now and I use it a lot.

[tiinytina]

Our Emerald II has an inline filter about 4" before the fuel pump.. I don't know if its original or a PO add on though..  Our had issues of not starting then running hot.. meece nest in airway (burning smell) ...   always something.. I want to pull the cowling and make sure the inner fins are clean etc....

Just wondering maybe a spider nest shorting control board... ?? seen that happen on water heater.

Tina

[ClydesdaleKevin]

Thanks for your replies Bluebird and Tina!

Bluebird,

According the Onan service manual for the NHE spec E generator, the ohm reading across the high tension leads is supposed to read between 34.0-41.6 k ohms.  Mine is reading way low at 14.6 k ohms.  + and - reads perfect at 4.2 ohms (the manual says it should read between 3.87 and 4.73 ohms).  So while the coil is working enough to start the genny, its simply not within specs so will have to be replaced.

The fuel pump definitely runs.  I can feel suction when I put my finger over the inlet, and you can hear the pump clicking away, even more so once the starter or solenoid gave up the ghost.  I tried to disassemble the pump to see if there was a screen or filter in there, but it doesn't appear that the pump body has anything on it that can screw off.  I'll take it all the way out later and see if I can disassemble it when its out...couldn't access it very well while it was in place. 

Unfortunately the NHE spec E Onan uses a starter with a remotely mounted solenoid.  I wish it was like my old Kohler, which used the windings as a starter and was fail proof. 

Tina,

While there SHOULD be a fuel filter somewhere, there certainly wasn't one in line.  I crawled under the rig and traced the line all the way back to the fuel tank, and nada.  So unless there is a screen or something in the fuel pump itself, then someone screwed the pooch when they installed it and didn't add a filter.

Ours is certainly capable of overheating...the insulation in the compartment is all coming off the walls and some of it is leaning into the air inlet, but it wasn't hot enough to shut itself down after running for just a couple of minutes.  When I fix this thing, I'll redo the insulation.

I didn't pull the circuit board all the way out, but there didn't appear to be any spider or bug nests in it.

The problem now is that there is yet another problem with the genny to address...the starter issue.  Onan parts are bloody expensive!  I'm hoping its just the solenoid, which is still probably expensive, but at least its easy to access...I'm not entirely sure where the starter is on this thing, and if its in the back of the unit, replacing it will require removing the genny from the compartment, since its not on a sliding tray.  Its a swing-down below the floor setup.

A new control board from Dinosaur is probably expensive too, but probably not nearly as expensive as a board from Onan...and its already been rewired for a Dinosaur board.

Just the new coil itself is going to cost a pretty penny, but at least the condenser should be reasonable.  Plugs are in decent shape, as are the wires, but I might go ahead and get new wires anyways, and new plugs and a new set of points.

I'm actually going to get a total price of all the parts and see what it all adds up to before fixing it.  I found an older model Emerald 3 on Craigslist in the Phoenix area with 25 original hours on it and running like a champ for 600 bucks.  I'll have to see how much parts will cost me for mine, which has well over 1000 hours on it.

Kev

[ClydesdaleKevin]

Okay...in another part of the manual, talking about another type of coil prior to spec G, it says the resistance at the high tension leads should be between 12.6 and 15.4 k ohms...so I guess my coil is good after all.  So there is that!

Kev

[ClydesdaleKevin]

And now I'm confused again.  No where in the whole service manual does it say where the starter is, and not one picture of where the starter might be in relation to the engine, etc.

And then I read in the troubleshooting section on sequence of events that some specs have a field flash starting setup, and some later specs use a starter.  But it doesn't say which specs.  Arrrgggg!!!  How can I tell if mine has a starter or is field flash?  It sounds like a starter...even whirrs a bit if it disengaged before the genny started, like on a car starter...but would a field flash setup make the same sound?  What...do I just trace the wires from the K2 solenoid and see where they go?  If its a starter, can it be converted to field flash?

I'd be convinced that it was a starter model, except that when I hit the start button, it draws a LOT of amps from the batteries to turn the genny over.  I would think that would be more indicative of a field flash setup, since a starter motor shouldn't draw that many amps. 

Hm?

Kev

[DonD]

This is a new to me resource:

www.flightsystems.com/pdf/onanrvtshootgd608.pdf



Field flash is a like polarizing a gen. Never heard of FF starting. Willing to learn for sure.

On some FPs there's a filter inside, twist an end cap to open.


4k starter;

Should be able to follow a large conductor to the starter?

[DaveVA78Chieftain]

Like shown in DonD's picture, starter is on back right hand side of unit below ignition coil.
When you hit start, K4 relay is energized which provides voltage to K1 starter solinoid, Ignition coil, and fuel pump during start cycle.  Make sure fuse F1 on A1 board is not blown.  Generator uses battery voltage to start.  Once it starts, it produces it's own voltage to run via K3.
Points based wiring diagram is on page 8-4.
Points based ignition coil test is on page 6-14 (12.6 to 15.4K ohms). 
Yes this generator is flashed during start up.
Appears there may be a fuel filter on carburator inlet fitting (later sets).

Dave

[ClydesdaleKevin]

Okay...gotta wait until the sun comes back to continue tests on genny.  Woke up this morning to the batteries reading 12.0 volts...it was overcast all day yesterday and it didn't help that mulitiple attempts to start the genny drained the batteries quite a bit.

Overcast again today and the back is fully charged and reading 12.7 volts, but we made sure we didn't use anything all day.

Thanks Dave and Don.  I'll have to blindly feel for the starter, since you can't see it from the front.  As far as the fuel pump goes, ours looks different from the one in your picture.  It is square bodied and doesn't appear to come apart anywhere, and looks sealed.  I'll have a closer look at it tomorrow.

Once the sun comes back I'll perform some more electrical tests at the relays to make sure they are getting voltage as required.

Kev

[ClydesdaleKevin]

Welp, I almost got an old Dodge Banner motorhome to use as a workshop for free, but the Faire had first dibs, and they took it.  But the owner was going to give me the Onan generator for free...a very old not running CCK with the exciter type cranking system (no starter).

So I WAS going to pull it in the morning, and then see about getting it running, and either replace my genny with it, or sell it on Craigslist and use the money to fix my genny.

Then I got home and just for the heck of it hit the start switch on my genny...and it turned over nice and fast and powerfully.  I guess my batteries were too low to turn the genny over when I tried last.

Still didn't start, but at least its not the starter!

After our first week here, I'm going to run a fuel line from a gas can right to the genny and see if it will turn over...that will at least eliminate fuel delivery from the equation.  I have a sneaking suspicion its not getting fuel unless my gas tank is well over 3/4...a throw back problem from when the in tank pump got knocked off its moorings. 

Could be the pickup tube was knocked loose, or else the rubber line is too porous from age.  I'm going to check that out first.

Once I cleaned the points and tightened all the wires, she did fire up and ran for a couple of minutes...and then died like it was out of gas.  And I was at just under 3/4 tank.  Almost like it used the gas up in the line and then stalled out.  Yes I could suck gas through the line, but it was slow coming out and sputtery, if you know what I mean.

So after the first week I'll test it out with a gas can and let you all know what I find out.

Which means I'm not going to take that old CCK after all.

Kev