Home » Public Forums » GMCnet » A different Onan question
| A different Onan question [message #180894] |
Sun, 19 August 2012 23:29  |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
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Today, I started to try and get the 4K Onan that came with, but was not installed, my coach.
I checked the oil, pulled the plugs, hooked up the battery and pressed the start button. Spun over but no spark. Pulled the cover off the points and they weren't moving. Realized that the points box was not down tight so I fixed that and set the timing. Hit the button and still no spark.
Went through the trouble shooting section in the manual and it tells me the board is dead.
So here is the question. What exactly does the board do? Can I bypass the board and just put hook the coil up like a car?
I don't mind buying the board but I sure would like to know that the generator actually generates and the motor runs works before start throwing money at it.
Second question is will the circuit board from a 6X work on the 4K? If so, I'll try the one on my parts coach.
I haven't checked compression yet but it 'feels' good. I'll deal with fuel issues when I get spark. The fuel pump runs which is a good sign. I'm expecting the carb will need to be cleaned up.
I really hate small engines. I do really well fabricating things and am a decent mechanic but electronics and I don't really speak to each other.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: A different Onan question [message #180901 is a reply to message #180894] |
Mon, 20 August 2012 01:26  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
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If the pump runs, then the board is not the source of your ignition not firing. Power to the pump and the ignition are run from the same board terminal (Pin 9).
If it were me I would connect a voltmeter to the + side of the coil and see it you have +12 volts there when cranking. If you do, then look at the minus side of the coil with a ohm meter and with the power off slowly turn the flywheel to see it the points are electrically opening and closing. If they are then the next thing is to see if the high voltage side of the coil and spark plug wires are good. Unplug BOTH spark plug wires and meter between them. There should be a reading of several thousand ohms. Please understand that the plugs fire in series. A problem with one plug or wire will affect the other one also. Make sure that the gaps are both set exactly. I believe the spec is .016 but look it up for sure.
Check all of that stuff, tell us what you find, and we will go from there.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] A different Onan question [message #180906 is a reply to message #180901] |
Mon, 20 August 2012 06:42 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Kerry,
Ken B's got you well in hand and will get you going. But he didn't answer
your question about what the board does.
Not very much, really: It serves to provide 12VDC to the ignition and fuel
pump only when the starter is engaged or the engine is running. Then it
monitors oil pressure and shuts the engine down if it drops. While the
engine is running, the board monitors the flywheel alternator (which has
very limited -- 8A, IIRC -- battery charging capability -- most aren't used
for that) and locks out the starter (in case the Onan remote is 100 yards
away so you can't hear it running). Ken B and I need that protection even
when standing beside it.
The 4kW and 6kW board are the same.
Ken H.
On Mon, Aug 20, 2012 at 2:26 AM, Ken Burton wrote:
>
> If the pump runs, then the board is not the source of your ignition not
> firing. Power to the pump and the ignition are run from the same board
> terminal (Pin 9).
> ..._____________________________________________
>
>
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Ken Henderson
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] A different Onan question [message #180936 is a reply to message #180926] |
Mon, 20 August 2012 12:10 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
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Kerry,
You should have 12VDC to the coil ONLY WHILE CRANKING or running. Is that
what you checked?
Ken H.
On Mon, Aug 20, 2012 at 11:08 AM, Kerry Pinkerton <Pinkertonk@mchsi.com>wrote:
>
>
> Ken(s):p I do not have 12V on the + terminal of the coil. When checking
> the wires, one goes to terminal 9 on the board. Nothing there either. Two
> more wires go to the fuel pump and solenoid, and one to a condenser. I'm
> assuming that the coil gets +12 from terminal 9?
> --
> Kerry
>
> North Alabama, near Huntsville
> 76 Eleganza being rebodied as an Art Deco car hauler
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] A different Onan question [message #180946 is a reply to message #180938] |
Mon, 20 August 2012 13:55 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
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Kerry,
That says the board is bad; probably relay K3. If you jumper pin 5 to pin
9, you should be able to start the engine with Low Oil Pressure (LOP) and
other protective functions disabled.
You may find this schematic a little easier to follow than that in the
manual. I drew it because I didn't like the original. It says for 4kW,
but it's equally applicable to 6kW. There are a couple of differences from
OEM (added prime switch and electronic ignition module) but they shouldn't
confuse anything.
Ken H.
On Mon, Aug 20, 2012 at 1:31 PM, Kerry Pinkerton wrote:
>
>
> Yes, only while cranking. No 12V at the coil or at #9 terminal.
> --
>
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] A different Onan question [message #180953 is a reply to message #180946] |
Mon, 20 August 2012 14:55 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
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Ken, If he has no voltage at Pin 9, How come he hears the fuel pump running? Did I misunderstand the original posting? I'll go back and look.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] A different Onan question [message #180955 is a reply to message #180952] |
Mon, 20 August 2012 14:59 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
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| Kerry Pinkerton wrote on Mon, 20 August 2012 14:54 |
What Schematic Ken??
|
Wrong Ken here but PM me your email address and I'll send you the schematic that Ken H. referenced. Ken H. does not do PM because he is a GMCnet email user.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] A different Onan question [message #180956 is a reply to message #180953] |
Mon, 20 August 2012 15:07 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Yes, the fuel pump clicks when I jump 9 to 5.
However, A new development. Just now, I went out and jumped 9 to 5, pump started clicking, cranked motor and checked power at the coil...nothing. Was about to check at post 9 when I smelled the magic smoke getting out somewhere. About this time the clicking stopped and I saw smoke coming off the rearmost stake on the heat sink over the fuel pump. Is that the Diode? Currently disconnected from the battery.
Can I put 12V directly on the coil from the battery without hurting the board...assuming it's not already hurt? If I can get the motor to spark I can siphon feed gas to verify the motor runs and then decide if I want to get the generator genning. If the motor is bad, then it's a waste of time and money to do anything else.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] A different Onan question [message #180958 is a reply to message #180956] |
Mon, 20 August 2012 15:18 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Yes, jumpering pin 9 to Pin 5 was suppose to put +12 directly on the coil. You can jumper +12 directly to the coil if you want. There is no ignition resistor to mess with like most automotive points ignitions.
The thing you saw smoking is the voltage regulator for the flywheel alternator. It is used only for charging the battery in early coaches with a separate starting battery.
PM me your email address and I'll forward you the schematic.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] A different Onan question [message #180960 is a reply to message #180958] |
Mon, 20 August 2012 15:34 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Thanks for the schematic. Does it matter that I've got the Onan on my bench and the coach meters/switches are not hooked up?
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: A different Onan question [message #180996 is a reply to message #180894] |
Mon, 20 August 2012 20:26 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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Thanks to a long phone call with Ken Burton, we succeeded in getting spark. THANKS Ken!
Four things were the problem...well five counting operator headspace.
Problem 1: Was my little alligator clip jumpers were not soldered and were not consistently reading. Swapped them out for some others and was getting consistent reading.
problem 2: The + terminal on my coil had 3 wire lugs stacked on top and there was some oxidation that was keeping them from making good contact. Broke the nut loose, wiggled things a bit, and re tightened the nut and I could read the voltage and was getting 12V at the + terminal when 9 & 5 were jumpered and the start button was pressed.
Problem 3: Was my lack of understanding that the TWO spark plugs must be grounded together because they fire serially. In other words, without them being physically touching either themselves OR the motor, THERE WILL BE NO SPARK. Tied them together with a clamp.
Problem 4: Was that my points, while set correctly, were not making and breaking electrically. After some serious work with a point file, they are making correctly and opening at 21 degrees BTC. They appeared to be new but I guess there was enough glaze and oxidation that they were not making contact.
So now I have a spark at the plugs and when I jump 9 to 5, my fuel pump runs. It will not run without the jumper which indicates a problem with my board...we think. Ken Burton suggested I contact Ken Henderson who is apparently the intergalactic expert on this circuit board. My electronics skills are pretty hopeless.
That said, I should be able to start and run the motor without the board in the loop (9 & 5 jumpered). That will tell me the first thing I need to know, that is, is the motor sound. Once I've determined that, I'll verify the generator is generating. If those two things work, I'll buy a new circuit board and probably do the Pertronics thing. Or try the board from the 6K Onan in the parts coach.
This is a great community!
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
[Updated on: Mon, 20 August 2012 20:27] Report message to a moderator |
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| Re: [GMCnet] A different Onan question [message #181019 is a reply to message #180976] |
Mon, 20 August 2012 22:20 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I emailed him a copy of the schematic that you made.
We got the ignition firing across the plugs but only by jumpering pins 9 to 5. K3 is not picking up. He had to cover off of the relay. He is going to work on getting it started and address the board problem after that.
He has a question on the wiring of the 120 volt side of the generator to the coach that I could not answer and my coach is not here to look at. I suggested that Kerry call you about it since you have pulled your Onan and wired in a Generac. I felt that you might be familiar with that area. I tried to telephone and conference you into the discussion but your cellphone went directly to voice mail. I did not leave a message.
I would have tried Rick Denny but I thought that he is probably out traveling around the country planning more traffic lights somewhere. I know there are others here that have worked in that area but at the time you and Rick came to mind.
It was a pleasure to work with someone over the phone who knew how to read a schematic and how use a volt and ohm meter. It sure made things a lot easier.
Now who knows about chain saws. I'm on my 3rd one trying to get it started. This one is brand new. I'm also getting too old to keep pulling that rope. I need an electric start chain saw.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] A different Onan question [message #181024 is a reply to message #181019] |
Mon, 20 August 2012 22:40 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Good. You must have had a long conversation with Kerry to find all those
problems. I'll help him if I can, but you know my CRS & it's been 5+ years
now since I had an Onan -- darned time flies, don't it?
With the demise of Honda & Generac, someone should put together a kit for
Onans: Pertronix ready to mount, all new wiring harness and simple modern
control board (DigiSpark?), and either a truly reliable carburetor or EFI.
Maybe even an automatic governor. Even if the kit cost $1000 it would
probably be worth it to make the Onan dependable in the absence of
competition. It should be do-able for no more than 1/2 that.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Mon, Aug 20, 2012 at 11:20 PM, Ken Burton <n9cv@comcast.net> wrote:
> ...
We got the ignition firing across the plugs but only by jumpering pins 9 to
> 5. K3 is not picking up. He had to cover off of the relay. He is going
> to work on getting it started and address the board problem after that.
>
> He has a question on the wiring of the 120 volt side of the generator to
> the coach that I could not answer and my coach is not here to look at. I
> suggested that Kerry call you about it since you have pulled your Onan and
> wired in a Generac.
...
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] A different Onan question [message #181085 is a reply to message #181019] |
Tue, 21 August 2012 10:17 |
Mr ERFisher
Messages: 7117
Registered: August 2005
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Looks like this one at end of manual
Gene
FREE WIFI @ Mickey D
On Aug 20, 2012, at 8:20 PM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> Ken Henderson wrote on Mon, 20 August 2012 18:33
>> Oh, haven't you heard?
>>
>> I NEVER succeed in sending links on the first effort.
>>
>> http://www.gmcmhphotos.com/photos/data/5813/KH_Onan_Wiring1.pdf
>>
>> Ken H.
>>
>> On Mon, Aug 20, 2012 at 3:54 PM, Kerry Pinkerton wrote:
>>
>>> What Schematic Ken??
>
> I emailed him a copy of the schematic that you made.
>
> We got the ignition firing across the plugs but only by jumpering pins 9 to 5. K3 is not picking up. He had to cover off of the relay. He is going to work on getting it started and address the board problem after that.
>
> He has a question on the wiring of the 120 volt side of the generator to the coach that I could not answer and my coach is not here to look at. I suggested that Kerry call you about it since you have pulled your Onan and wired in a Generac. I felt that you might be familiar with that area. I tried to telephone and conference you into the discussion but your cellphone went directly to voice mail. I did not leave a message.
>
> I would have tried Rick Denny but I thought that he is probably out traveling around the country planning more traffic lights somewhere. I know there are others here that have worked in that area but at the time you and Rick came to mind.
>
> It was a pleasure to work with someone over the phone who knew how to read a schematic and how use a volt and ohm meter. It sure made things a lot easier.
>
> Now who knows about chain saws. I'm on my 3rd one trying to get it started. This one is brand new. I'm also getting too old to keep pulling that rope. I need an electric start chain saw.
>
> Ken B.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
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I do not have 12V on the + terminal of the coil. When checking the wires, one goes to terminal 9 on the board. Nothing there either. Two more wires go to the fuel pump and solenoid, and one to a condenser. I'm assuming that the coil gets +12 from terminal 9?