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SA electrical problems

M

Mark

Well-known Member
I don"t really know where to start explaining my problem....so bear with me as I attempt to describe my woes.

I have been trying to figure out why my tractor suddenly quit running. I fired it up a few days ago and after about one minute, it died as if it ran out of gas.

I took the fuel line loose, sediment bowl and finally removed the carburetor and went through it. While I had it off, I even put a kit in it. That didn"t solve a thing.

Hmmm, says I.

So, I go to the other side and begin inspecting the ignition. Hot wire is fine to the coil.

Inspecting the points, I find them pitted pretty badly and they only have about 15 hours run time on them. The plug wires were pretty sad as well, so, in went all new ignition components....everything. Points set at .020, plugs at .023 as per the book. The new wires went back on according to the book schematic 1-3-4-2.

Still, the tractor refuses to start. Thinking there was a possibility of having the wires on wrong....I even advanced them all on socket ahead and then went in the other direction. Of course, I got backfires and such....but that proved to me the wires were on right to begin with.

I then hotwired it.....ran a wire from the positive battery post to the coil....once, it seemed like it wanted to fire.

Hmmm, again.

This tractor had been converted to 12 volt before I got it and I had never had any problems, therefore I never messed with the wiring.

I found it still has a 6 volt coil. The battery wire has been ran to a ballast resistor and from there to the coil negative post and the positive coil post to the distributor.

I am no electrician....but I would think the 12 volts being ran to the resistor, hypothetically anyway...should reduce it down to 6 volts. Being a positive charge......shouldn"t the ballast wire then attach to the positive terminal of the coil and then the negative coil post go to the distributor?

I talked this over with a friend and he said I should have a 12 volt coil with the positive battery wire ran to it"s positive post and then ballast resistor going between the negative coil post and the distributor.

Am I confused? Damn right, I am!

With all the ignition components being fresh EXCEPTING the coil, I cannot fathom why this engine refuses to start, UNLESS the coil is bad.

So, if the coil is going dead and considering the tractor has been converted to 12 volts (battery and alternator).......what volt coil do I need and how should the ballast resistor be wired to the coil?

If all this is clear as mud, I apologize. It"s the way I knew to explain my problem. Thanks.
 
First is the polarity of the coil. If it has an alternator, it is very likely a negative ground battery and charging system. This means the coil negative should be grounded (through the distributor/points)
Second is the timing. With #1 on TDC, The points should just be breaking, with the rotor pointing to #1 wire terminal in the cap.
If these are right, pull the coil wire away from the cap, and place it 1/4" away from the block.
Open the cap, and use the tip of a screwdriver to open and close the points. If there is a nice blue spark it should run. If not suspect the coil. JimN
 
A couple of thoughts.

It very well could be a bad coil from what you describe. As far as replacing it, you have the choice. a) get a 6v coil, and continue using a ballast resistor inline between the battery and the coil or b) get a 12v coil, which delivers the same output to the distributor as the 6v, by being wound differently internally than the 6v coil, and eliminates the need for the inline ballast resistor.

The badly burned points could be a matter of the ignition being left on with the tractor stopped (also hard on coils!), but could also be a symptom of too much voltage. What do you have for a ballast resistor? If one of the old Chrysler types, could it be hooked up to the wrong side (the side without resistance) so that it's delivering the full 12v to the 6v coil?

As far as what goes where, the wire from the coil to the points in the distributor should be the same as the ground on your battery. If you're like most 12v and use a negative ground, the wire to the distributor should also be on the (-) stud of the coil, and the lead from the battery to the coil on the (+) stud.
 
(quoted from post at 19:12:08 11/02/09) I don"t really know where to start explaining my problem....so bear with me as I attempt to describe my woes.

I have been trying to figure out why my tractor suddenly quit running. I fired it up a few days ago and after about one minute, it died as if it ran out of gas.

I took the fuel line loose, sediment bowl and finally removed the carburetor and went through it. While I had it off, I even put a kit in it. That didn"t solve a thing.

Hmmm, says I.

So, I go to the other side and begin inspecting the ignition. Hot wire is fine to the coil.

Inspecting the points, I find them pitted pretty badly and they only have about 15 hours run time on them. The plug wires were pretty sad as well, so, in went all new ignition components....everything. Points set at .020, plugs at .023 as per the book. The new wires went back on according to the book schematic 1-3-4-2.

Still, the tractor refuses to start. Thinking there was a possibility of having the wires on wrong....I even advanced them all on socket ahead and then went in the other direction. Of course, I got backfires and such....but that proved to me the wires were on right to begin with.

I then hotwired it.....ran a wire from the positive battery post to the coil....once, it seemed like it wanted to fire.

Hmmm, again.

This tractor had been converted to 12 volt before I got it and I had never had any problems, therefore I never messed with the wiring.

I found it still has a 6 volt coil. The battery wire has been ran to a ballast resistor and from there to the coil negative post and the positive coil post to the distributor.

I am no electrician....but I would think the 12 volts being ran to the resistor, hypothetically anyway...should reduce it down to 6 volts. Being a positive charge......shouldn"t the ballast wire then attach to the positive terminal of the coil and then the negative coil post go to the distributor?

I talked this over with a friend and he said I should have a 12 volt coil with the positive battery wire ran to it"s positive post and then ballast resistor going between the negative coil post and the distributor.

Am I confused? Damn right, I am!

With all the ignition components being fresh EXCEPTING the coil, I cannot fathom why this engine refuses to start, UNLESS the coil is bad.

So, if the coil is going dead and considering the tractor has been converted to 12 volts (battery and alternator).......what volt coil do I need and how should the ballast resistor be wired to the coil?

If all this is clear as mud, I apologize. It"s the way I knew to explain my problem. Thanks.
Click to expand...

Mark, it was previously running just fine the way it was wired, so unless it re-wired itself when you were not looking, you are looking in all the wrong places for your problem. Most people match the battery + or - to the same sign on the coil + or - and many think that it makes a significant difference, but it really doesn't do anything except change the polarity (+/-) of the spark & depending on how the windings are connected internal to a specific coil, alter the HV by maybe as much as 1%. The coil & resistor are in series, so the order is of no consequence whatsoever, but again, most will place the resistor between the ignition switch and the coil.
Watch the points when spinning the engine. Do you see a spark at the points? You should.
 
With respect, the resistor between the coil and distributor is very different than having it before the coil. The primary current is strongly affected by the condenser in the distributor. This should be directly connected to the coil neg side in this case. The companies and that built coil and point systems for years did not put the resistance between the interacting components. JimN
 
disconnect the wire from ign. switch side of resistor check voltage if it has voltage when the ign. is on , bypass the resistor they will go bad ,if it starts that's your problem, if it want fire up test spark from coil as mentioned earlier.
 
(quoted from post at 20:15:26 11/02/09) With respect, the resistor between the coil and distributor is very different than having it before the coil. The primary current is strongly affected by the condenser in the distributor. This should be directly connected to the coil neg side in this case. The companies and that built coil and point systems for years did not put the resistance between the interacting components. JimN
Click to expand...

With all due respect, Jim, when reduced to it's simplest equivalent, it is a simple series circuit, and we both know position of the elements in the series does not matter.
It is just a physically cleaner installation wiring wise to put it where the makers put it.
equiv_ckts.jpg
 
Hot damn, I see seeds of progress!

I offer my thanks for the excellent information, given in terms I can understand. You have educated me immensely on the proper battery/resistor/coil wiring scheme. For those of you with a strong grasp of those things....it is all elementary, but for me it is pure alchemy!

By process of elimination, there remains only one weak link in the chain.....the coil. Now, knowing that a 12 volt coil can be used sans the resistor....because a 12 volt coil is wound differently and therefore delivering the same voltage to the distributor.....I have been enlightened. Not only was I told what to do, it was explained WHY/HOW it works. That is quality teaching gentlemen and my hat is off to each of you. I do confess the electrical schematics tossed me out in left field, no different from reading cuneiform or hieroglyphics...hehe!

Now, waiting for daylight and a new coil, hopefully producing positive results.

And one short comment on my questioning of how the resistor was wired into the circuit: True enough, the tractor ran fine as wired. However, after finding the points badly burned after only 15 hours of service, it caused me to wonder if the voltage was being reduced and if the resistor had been wired into the circuit improperly and hence, negating it's intended purpose....which would cause the points to fry from high voltage.
 
> With respect, the resistor between the coil and
> distributor is very different than having it
> before the coil.

No it isn"t.

As long as the coil and resistor are in series and nothing is in parallel with either the same current flows through both. Order doesn"t matter.
 
Again with respect. In a simple circuit you are correct. There are two differences (in my reasoning) the first is the fact that part of the current flow is to the sparkplug (and thus ground) that is generated by the discharge (collapse) of the flux in the coil as points break. The second is the LC interaction between the coil and ground as in the clip from Wiki.

At the same time, current exits the coil's primary winding and begins to charge up the capacitor ("condenser") that lies across the now-open breaker points. This capacitor and the coil’s primary windings form an oscillating LC circuit. This LC circuit produces a damped, oscillating current which bounces energy between the capacitor’s electric field and the ignition coil’s magnetic field. The oscillating current in the coil’s primary, which produces an oscillating magnetic field in the coil, extends the high voltage pulse at the output of the secondary windings. This high voltage thus continues beyond the time of the initial field collapse pulse. The oscillation continues until the circuit’s energy is consumed.
If it is run on a scope, and is clearly the same pattern, I would be amazed. Jim
 
A failing coil can cause excessive point current even if it is still working. If the primary windings are shorting to one another the coil is not shorted to ground, it is just lower in internal resistance. Thus a hotter ballast resistor, and burned points with the system still functioning. JimN
 
Well, you're welcome, Mark! Give it a try, and start a new thread to let us know how you're making out with it.
 
Problem is probably condenser. Put a little gasoline in a tin lid and jump spark to it. If it does not set gasoline afire, then replace condenser. Have had this problem myself. This was told to me by an old mechanic who assembled Farmalls in the 1940's and worked on them everafter.
 
You say the resistor is between the coil and dist correct. The resistor should be BEFORE the coil.If you are wired as you said wire the rest Before the coil.
 
Sorry I arrived late, but as an electrical engineer I love this sparky chat......A couple engineering points.....


1) I AGREE WITH JIM (janicholson) the location of the ballst resistor DOES MAKE A DIFFERENCE which is why factory set ups ALWYAS had the ballast BEFORE the coil NEVER between it and the points YUKKKKK. Sure its a series LR circuit when the points are closed and at steady state during that time the condensor is shorted out by the closed points (LR ONLY),,,,,,,butttttttt when the points open then its a series LRC circuit and theres ringing and oscillation occuring between the condensor and coil (thats just an LC circuit mostly) until its all damped out i.e. the condensor charges up and stores energy but then it gets discharged (back into the coil), (Ive seen oscilloscope prints of that action). In the factory wiring the coil and condensor are next to each other in series with NO RESISTANCE BETWEEN THEM (its BEFORE the coil remember) any resistance between them (when the ringing oscillation occurs) would serve to discharge energy in the form of wasted heat versus it getting fed back direct to the coil where that energy gets transformed into magnetic energy storage and transfer over to the secondary and out to the plugs where it does more good then the ballast wasting it as heat.


2) THE COIL POALRITY WIRING INDEED ALSO MAKES A DIFFERENCE Why you think the factory bothers to label those lil terminals + and - ??????????. Its easier to discharge electrons from a hotter surface (plug electrode) to a relatively cooler (plugs ground strap) surface. Thats why in vacuum tubes theres a heater located under the cathode to HEAT IT UP to easier emit electrons up to the cooler non heated plate. A retired physicist friend of mine actually took measurements of firing voltages when coil leads were correct but then reversed and found it was several thousand volts less if the coil was wired correct. i.e. if at reverse polarity the coil has to work harder and heats up more and is less efficent becasue it takes more voltage to arc jump the gap if the electrons have to flow from a cold to a hotter surface. SURE she still sparks either way butttttttttt its more efficient and the coil wastes less energy in heat if its wired at the correct polarity.

DISCLAIMER hey its IMPOSSIBLE to explain the Kettering coil ignition system in a few sentences here as that takes entire books and years of study to accomplish, so the above is wayyyyyyyyyyyyyy over simplified and perhaps not 100% perfect but its how I best recall it works and WHY THE BALLAST GOES BEFORE THE COIL AND THE COIL POLARITY MAKES A DIFFERENCE. I graduated from Purdue EE in 1969/1970 so Ive slept some since then lol but this is my ebst effort to help yall (especially non electrical engineers and technicians) understand

God Bless yall for your help here

Ol John T BSEE,JD in Indiana

PS My Ignition Troubleshooting may also help the original poster
Ignition Troubleshooting
 
(quoted from post at 10:10:24 11/03/09) Sorry I arrived late, but as an electrical engineer I love this sparky chat......A couple engineering points.....


1) I AGREE WITH JIM (janicholson) the location of the ballst resistor DOES MAKE A DIFFERENCE which is why factory set ups ALWYAS had the ballast BEFORE the coil NEVER between it and the points YUKKKKK. Sure its a series LR circuit when the points are closed and at steady state during that time the condensor is shorted out by the closed points (LR ONLY),,,,,,,butttttttt when the points open then its a series LRC circuit and theres ringing and oscillation occuring between the condensor and coil (thats just an LC circuit mostly) until its all damped out i.e. the condensor charges up and stores energy but then it gets discharged (back into the coil), (Ive seen oscilloscope prints of that action). In the factory wiring the coil and condensor are next to each other in series with NO RESISTANCE BETWEEN THEM (its BEFORE the coil remember) any resistance between them (when the ringing oscillation occurs) would serve to discharge energy in the form of wasted heat versus it getting fed back direct to the coil where that energy gets transformed into magnetic energy storage and transfer over to the secondary and out to the plugs where it does more good then the ballast wasting it as heat.


2) THE COIL POALRITY WIRING INDEED ALSO MAKES A DIFFERENCE Why you think the factory bothers to label those lil terminals + and - ??????????. Its easier to discharge electrons from a hotter surface (plug electrode) to a relatively cooler (plugs ground strap) surface. Thats why in vacuum tubes theres a heater located under the cathode to HEAT IT UP to easier emit electrons up to the cooler non heated plate. A retired physicist friend of mine actually took measurements of firing voltages when coil leads were correct but then reversed and found it was several thousand volts less if the coil was wired correct. i.e. if at reverse polarity the coil has to work harder and heats up more and is less efficent becasue it takes more voltage to arc jump the gap if the electrons have to flow from a cold to a hotter surface. SURE she still sparks either way butttttttttt its more efficient and the coil wastes less energy in heat if its wired at the correct polarity.

DISCLAIMER hey its IMPOSSIBLE to explain the Kettering coil ignition system in a few sentences here as that takes entire books and years of study to accomplish, so the above is wayyyyyyyyyyyyyy over simplified and perhaps not 100% perfect but its how I best recall it works and WHY THE BALLAST GOES BEFORE THE COIL AND THE COIL POLARITY MAKES A DIFFERENCE. I graduated from Purdue EE in 1969/1970 so Ive slept some since then lol but this is my ebst effort to help yall (especially non electrical engineers and technicians) understand

God Bless yall for your help here

Ol John T BSEE,JD in Indiana

PS My Ignition Troubleshooting may also help the original poster
Ignition Troubleshooting
Click to expand...

Well, John, I like a lot of your posts, but this last one isn't totally on the mark. ALWAYS (as in ballast always goes before the coil) is a big word.......see Attachments. Clearly these Delco engineers didn't know about 'always' (Delco, home of Alfred Kettering).
contact_triggered_Delco.jpg

contactless_Delco.jpg


You say condenser discharges back into the coil with no resistance between them. For the condenser to coil transfer to take place, current must flow from condenser to coil and current must have a loop in which to flow AND no matter where that resistor is physically located, that current flows thru it and the battery and the connections of condenser to ground thru ground thru connections to battery. So, no it does not matter electrically where the resistance is located. I don't need to see "oscilloscope prints), I can see the real thing in my shop now or any time on this set up as it exist at this very moment.......come on over any experiment all you like. Welcome anytime.
2ndcoiltester.jpg

full_cycle_withcurrent_sml.jpg



I didn't say polarity didn't make ANY difference, just not significant difference. Yes, I am fully aware of thermionic emission, just like your self. It's nice, but clearly not very important for several reasons, 1) it isn't there when you need it most at cold starts, 2)magnetos work just fine where every other spark is of opposite polarity, 3)all old Harley's used one coil where each plug received output from opposite ends of coil, so half the sparks were of one polarity & half the other polarity, 4) many current day electronic ignition engines use fewer coils than cylinders (3 coils for 6 cylinders for example) and result is half run on negative polarity spark and half run on positive polarity spark (how is you Ford V6 running?).

Yes, I'm an 'outsider' and Jim, Gene, John are all insiders, but I'm not wet behind the ears and support my position with facts, but still will be beat about the head & shoulders anyway.
In so many of these things I'm bothered by the acceptance of various things 'because that's the way they have always been', rather that by a factually supported answer to the question, "why?". A daughter ask her mother, 'why do you always cut the end of the ham bone off & drop in in the pan beside the ham?".. Mother responds, 'because my mother always did it that way'. So, the daughter goes to he grandmother an ask her 'why she cut the end off & dropped in in beside the ham?'. Grandmother said, "because I never had a pan big enough to fit the whole ham". Took couple generations, but it was learned, 'why'.
 
Totally interesting!!
In your examples the "ballast resistors" are still outside of the relationship between the switching element (triggered transistors, and low current points) and the inductor.
I think John and I stand pat on out proposition.
Jim
 
(quoted from post at 15:25:09 11/03/09) Totally interesting!!
In your examples the "ballast resistors" are still outside of the relationship between the switching element (triggered transistors, and low current points) and the inductor.
I think John and I stand pat on out proposition.
Jim
Click to expand...
Jim, I don't know why you think my position is so interesting. I find yours much more interesting, in that my some magic you seem to have found a way to move the charge back & forth between the coil and the condenser without a closed loop circuit (as would be required in my humble opinion, as shown in green). You can demonstrate that magic to everyone by making the bulb light by transferring energy from the battery to the light bulb (without my green connection), as well. Not much of a position to 'stand pat on". :cry:
current_flow.jpg
 
The spark is a connection. It is connected with wire to the electrodes, and across the electrodes by way of the ionized gasses in the spark to ground. Does it do so -- yes.
I admit the conduction through the resistor as valid, I would not deny it exists will it make a usable ignition spark I guess it might be operational to a degree, I would not put an ignition together that way.

Spark is often created by turning off the key and collapsing the system. Sometimes causing a terrific backfire. Where is the connection to the resistor then!!! JimN
 
(quoted from post at 17:39:48 11/03/09) The spark is a connection. It is connected with wire to the electrodes, and across the electrodes by way of the ionized gasses in the spark to ground. Does it do so -- yes.
I admit the conduction through the resistor as valid, I would not deny it exists will it make a usable ignition spark I guess it might be operational to a degree, I would not put an ignition together that way.

Spark is often created by turning off the key and collapsing the system. Sometimes causing a terrific backfire. Where is the connection to the resistor then!!! JimN
Click to expand...
"Ign key....where is the connection thru the resistor then?" The connection at that time is thru the arc across the contacts of the opening key switch....the exact equivalent of points opening in the absence of a condenser....still get a spark, although a weak one, since so much of the energy stored in the coils magnetic field is turned into heat in the arc across the opening switch or points instead of passing to the HV circuit. With the condenser, not as much "sharing' takes place , with more going to the HV and less lost at the points.
 
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