Super C not starting, I think coil issue

Hello everyone!

It has been a crazy past few months, and I have been super busy trying to finish out my semester of college online and also trying to stay safe and manage other aspects of my life.

I finally have some more free time, so I have been using my Farmall Super C more around my property for pulling out bushes, dragging some logs, and other work.

Recently, I was running the tractor and when I opened up the throttle almost all the way, it started sputtering. I closed the throttle almost to idle and the engine starting running smoothly again. Then, a minute later, I opened up the throttle again and the engine immediately shut off. I have not been able to start it since then.

The starting motor is definitely working, and there is definitely enough gas in the tractor. I checked gas flow to the carb and it seems to be getting a very good flow.

Using a simple test light, I checked the electrical system to see if a faulty wire was to blame. The test light lit up when I checked both sides of the resistor above the coil, so clearly the resistor is getting electricity.

Then, I checked the two wires that go out of the coil, I am not sure what they are called. They both lit up my test light, so I do not think that is the problem. The one wire that goes from the coil to the side of the distributor also lit up at both ends.

The one area where I think there might be a problem is the connection between the coil and distributor cap. I do not know the terminology, but it is the big thick black wire (similar looking to the ones that go from distributor cap to spark plugs) that connects in the middle of the distributor cap and runs to the center of the one side of the coil.

How do I test if that big black wire from the coil to distributor cap is getting electricity? Should I be able to feel a spark?

I attached a picture that shows what I mean.

Thank you very much,

John

First pull out a plug and see if you have good spark. If not-Go back and check the short yellow wire that goes between the coil and distributor. Your light should be blinking if you turn it over. If not, your points are bad/ or tarnished. If you do have good spark, look at the fuel side of it, ie possible crud in the carb got stirred up.

John that coil wire end (High tension wire out top of coil to dist cap center) looks questionable, it usually has a rounded metal
termination (not just a short bit of coil wire) that fits down tight in the coils top center HV tower. While the spark might still jump
what you show is NOT proper and needs corrected with a new coil wire (top center HV coil tower to center of dist cap).

If you put a 6/12 test lamp (or use a volt meter) on the coils small side input terminal that's wired to the ballast resistor, it should
come ON anytime the Ign Switch is turned ON...............Place it next over on the coils other small side terminal (one that wires to side
of distributor) turn on ignition and crank engine over IT SHOULD FLASH ON (when points are open) BUT GO OFF (when points are closed).... If
it never flashes ON and OFF shes not gonna work right. If it stays on regardless of engine or dist position or when cranked over shes never
gonna work...

NOTE to your statement "Then, I checked the two wires that go out of the coil, I am not sure what they are called. They both lit up my
test light, so I do not think that is the problem"

Again, the small side input terminal should come on and stay on anytime ign switch is on HOWEVER the lamp on the coils other output to
dist terminal should only be ON if points are open but go off if closed IF IT STAYS ON shes never gonna fire because a good set of working
and proper gapped points should close fully which takes that to ground causing the light to go off

You need to take the dist cap and dust cap off and insure the points are good and gapped closing fully AND NOT BADLY BURNED OR CARBONED OR
PITTED SO BADLY they arent workign and the light going off when they are closed

BOTTOM LINE that coil wire end looks BAD and the points may be burned or pitted or not fully closing. They may need replaced if badly
burned or pitted. If only gray oxide coated you may be able to clean/buff/polish them but if bad burned a points file might get you by but
Id replace them.

CHECK THE POINTS THAT MAY BE THE PROBLEM !!!!!!!!!!!!!!!!

Im sure I missed a few possibilities, I only intended to cover a few of the most basic, hopefully others can add more to this and other
possible problems. Most are probably in my Troubleshooting procedure

For a more detailed step by step procedure to find the problem copy and print my Troubleshooting Procedure and work through it.

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=5745

John T
John Ts Ignition Trouibleshooting

Check your points with the test light and fuel supply as stated.
If other testing doesn't find the problem, it could be a sheared pin on the distributor shaft gear. I have seen this happen more than once. Spit Sputter and Stop.
The easiest way to check for a sheared pin would be to check the timing.

Thanks for all the help guys.

That wire that you mentioned looks bad got damaged when being unplugged, it was a little stuck I think. But, I was able to fix that damaged wire I think by cutting some of the plastic sheath off and feeding the copper wire back through the brass end cap just like the other end of the wire.

I will follow the troubleshooting and tips you guys gave and see what I find.

Thanks,

John

There is good info here for you. To answer two of your questions.

"How do I test if that big black wire from the coil to distributor cap is getting electricity? Should I be able to feel a spark?"

This is a quick check for spark from the coil. If you have spark at the plugs it is coming through this wire. To check the coil wire itself; with the coil wire plugged back in the coil, hold the distributor end of the wire about 1/8" from a bare spot the block and crank the engine over (grip the wire on the insulation, back away from the end, with insulated handle pliers or such). You should see a good spark jump to the block. Keep increasing the distance and see how far the spark will jump, it should make 1/4" or more.

As far as should you be able to feel a spark -- If you do feel it once, you will want to avoid such in the future. It is the same high voltage that goes to the spark plugs and not really good for you. If the wire's insulation is good you won't feel it through the insulation. If you do get shocked through the insulation of a dry coil or spark plug wire, the wire needs to be replaced. Wet wires will show leakage easier and may be nearing time to replace. This is why some engines won't start or quit if they are in the rain. Good tight boots on the wires at the posts help avoid that problem.

To test an electrical system it's handy to get a volt meter. It will not only tell you there is voltage there but the amount. Harbor Freight has a pretty good one they used to give away but is certainly cheap
enough to buy at six bucks.

I wouldn't want to feel if the coil is creating a spark. The spark from an engine hurts as bad as touching household electricity.

From the second picture I would lean toward the coil wire as being the problem. The metal end of the wire is missing. If the wires are in that rough condition it would probably be a good idea to replace the
spark plug wire set. They make a spark plug wire tester which sort of looks like a tire pressure gauge you just lay on the wire while someone cranks and it will light up when there is a spark.
https://toolsquik.com/lisle-ls19380-spark-tester/

quick and simple check remove a plug hook it to the wire and ground the plug to see if you have fire to the plug cause now you do not know whether you have fire or fuel

(quoted from post at 08:51:58 05/19/20) There is good info here for you. To answer two of your questions.

"How do I test if that big black wire from the coil to distributor cap is getting electricity? Should I be able to feel a spark?"

This is a quick check for spark from the coil. If you have spark at the plugs it is coming through this wire. To check the coil wire itself; with the coil wire plugged back in the coil, hold the distributor end of the wire about 1/8" from a bare spot the block and crank the engine over (grip the wire on the insulation, back away from the end, with insulated handle pliers or such). You should see a good spark jump to the block. Keep increasing the distance and see how far the spark will jump, it should make 1/4" or more.

As far as should you be able to feel a spark -- If you do feel it once, you will want to avoid such in the future. It is the same high voltage that goes to the spark plugs and not really good for you. If the wire's insulation is good you won't feel it through the insulation. If you do get shocked through the insulation of a dry coil or spark plug wire, the wire needs to be replaced. Wet wires will show leakage easier and may be nearing time to replace. This is why some engines won't start or quit if they are in the rain. Good tight boots on the wires at the posts help avoid that problem.

Click to expand...

Thanks Jim.

I am 19 years old and trying to get a better understanding of all parts of my tractor. I feel like I am learning a lot thanks to everyone on this forum.

I do not live on a farm, I actually live in a suburban neighborhood, but I love old tractors and want to own a farm when I get out of college sometime. Nothing huge, maybe just a couple acres as a hobby. I am majoring in engineering.

One more question about the electrical system. From what you said, the main thick black wire that goes from coil to the center of the distributor is what provides the spark plugs with electricity. What is the purpose of the yellow wire in my picture that also goes from the coil but connects to the side of the distributor? It is the smaller, thinner wire.

(quoted from post at 10:56:12 05/19/20) quick and simple check remove a plug hook it to the wire and ground the plug to see if you have fire to the plug cause now you do not know whether you have fire or fuel

Click to expand...

Gene, when you say remove a plug and hook it to the wire, what exactly do you mean? I know this is probably a novice question.

[/qoute]Thanks Jim.

I am 19 years old and trying to get a better understanding of all parts of my tractor. I feel like I am learning a lot thanks to everyone on this forum.

I do not live on a farm, I actually live in a suburban neighborhood, but I love old tractors and want to own a farm when I get out of college sometime. Nothing huge, maybe just a couple acres as a hobby. I am majoring in engineering.

One more question about the electrical system. From what you said, the main thick black wire that goes from coil to the center of the distributor is what provides the spark plugs with electricity. What is the purpose of the yellow wire in my picture that also goes from the coil but connects to the side of the distributor? It is the smaller, thinner wire.[/quote]ttps://forumphotos.yesterdaystractors.com/photos/mvphoto55195.jpg[/img]

John V, your question "What is the purpose of the yellow wire in my picture that also goes from the coil but connects to the side of the
distributor? It is the smaller, thinner wire."

ANSWER the small yellow wire that leads FROM the coils small LV Primary terminal TO the small terminal on the side of the distributor
is to conduct the coils LV primary current to the distributor and its internal contact points. When the points are closed current flows
through the coils LV Primary to ground via the closed points and when the points break open coil current suddenly stops.

The coils other LV primary terminal is what gets voltage via the ballast resistor when the ignition is turned on.

A test lamp on the coils LV primary output (small yellow wire to distributor) as engine is cranked over needs to flash ON when points are
open but go off when they are closed.

Got it ???

John T
John Ts Ignition Troubleshooting

(quoted from post at 10:56:33 05/19/20)

Gene, when you say remove a plug and hook it to the wire, what exactly do you mean? I know this is probably a novice question.

Click to expand...

Take the wire off a spark plug. Screw out the plug, them put the wire back on it. Lay the plug on the frame or let it hang in such a way that the base of the plug is touching the frame--i.e. grounding it. Then turn the engine over and watch the end of the plug to see if it produces a spark. Ignition must be on, of course.
Hope that helps.

John, the coil may be bad HOWEVER I first suspect the points is the problem. I thought I already told you this ????? but here goes again.

1) If you put a 6/12 test lamp on the coils small side input terminal that's wired to the ballast resistor, it should come ON anytime the
Ign Switch is turned ON DOES IT ?????????

2) Next, Place it over on the coils other small side terminal (one that wires to side of distributor) turn on ignition and crank engine
over IT SHOULD FLASH ON (when points are open) BUT GO OFF (when points are closed).... If it never flashes ON and OFF shes not gonna work
right. If it stays on regardless of engine or dist position or when cranked over shes never gonna work...

IF IT STAYS ON shes never gonna fire because a good set of working and proper gapped points should close fully which takes that to ground
causing the light to go off. If badly burned or not closing she cant fire

IF IT STAYS OFF shes never gonna fire because the points are shorted or condensor is shorted or the distributors side stud pass thru is
shorted.

You need to take the dist cap and dust cap off and insure the points are good, clean, and gapped and are closing fully AND NOT BADLY BURNED
OR CARBONED OR PITTED SO BADLY they aren't working.

Its possible to test the coil with an ohm meter to see if its total BAD like a short or an open HOWEVER it can pass low voltage low energy
ohm meter tests yet still be bad upon high voltage and HV breakdown and once it warms up

OKAY for your help I have copied and pasted my troubleshooting Procedure to tell what the problem is but you ahve to work through it

TROUBLESHOOTING A BATTERY POWERED EXTERNAL COIL TYPE IGNITION SYSTEM:
PRELIMINARY CHECKS:

(A) To see if it happens to be a cap n rotor problem and to see if at least the coil is firing, remove the coil wire from the distributor
(leave coil end intact) and place its bare end to within 1/8 inch from tractor iron, turn her on n crank her over, and see if she jumps
that gap with a good visible blue spark?????? If so but the plug wire ends (from wire end to 1/8 inch to frame) or the plugs themselves
don?t fire, its a cap n rotor or plug wire problem. If the coil wire isnt even sparking, see below.

(B) Next open the cap and see that the points are gapped correct and indeed opening and closing as the engine is cranked and the
distributor shaft rotates and MAKE SURE THEY ARE NOT BURNED OR PITTED OR CARBONED UP BADLY !!!!!!!!!!!! If so, running a point file between
them to clean them up might make her run again HOWEVER that?s only a temporary cure, so if that cleaning makes her spark, INSTALL N GAP NEW
POINTS. In the event they appear good but only gray oxide coated, non abrasively clean/buff/polish them using say a dollar bill or shop
cloth etc. and see what happens.

MORE TROUBLESHOOTING IF ALL THE ABOVE STILL FAILS TO MAKE HER SPARK

1) THE VERY FIRST THING YOU GOTTA HAVE is voltage to be present on the coils high supply (NOT to distributor) terminal when you turn the
Ignition switch ON. If not she cant ever fire, but in the event the ignition switch or circuit/wire down to the coil or any Ballast
Resistor is bad or open, you can HOT WIRE it by jumping a hot ungrounded battery voltage source to the coils high input supply (NOT to
distributor) side n see if she runs then???? If she fires hot wired, you could have a bad ignition switch ((That can happen, when Ignition
is on, the switches IGN terminal must turn hot)),,,,,,,or an open Ballast (if it has one) or a bad/open wire from switch to coil.

If the switch is good, if you turn the ignition switch on and place a test lamp on the coils high (NOT to distributor) terminal SHE MUST
LIGHT UP. If not again, look for an open Ballast Resistor (if it has one, it should read around 1.25 to 2 ohms across its terminals) or
bad/open wires from the switches IGN output down to the Ballast (if it has one) and distributor.

2a) When the Ignition switch is turned on, voltage should appear on the coils high input side. That would be 6 volts on a straight 6 volt
system or 12 volts on a 12 volt non external ballasted system, or around 6 volts on a 12 volt system that used a 6 volt coil plus an
external Ballast Resistor and the coil is good and the points are closed and they and ALL wiring is good.

2b) To insure the coils low voltage primary winding is not bad/open, use an ohmmeter and measure its DC resistance between its lil + and -
terminals. If its an open circuit (no continuity) its bad/open and will NOT work. It should measure around 1.25 to 2 ohms or so if its a 6
volt coil and maybe 2.5 to 3.5 if its a 12 volt internally ballasted coil. NOTE CAUTION have all leads and any voltage source DISCONNECTED
FROM the coil for this simple primary winding continuity test. 3) Next, place your voltmeter or test lamp over on the coils other low to
distributor terminal side, turn her on and crank the engine over.

4) A test lamp there should flash ON (when points are open) and OFF (when points are closed) as the engine is cranked slowly.

5a) If the lamp never comes on there, the coils primary is bad/open,,,,,,,,,,or the points are never opening,,,,,,,,,or theres a
shorted/bad condensor (remove its lead to points and see if lamp comes on, if so, bad shorted condensor or its wiring),,,,,,,,or the points
wire is shorted,,,,,,,,or the distributors side pass thru stud is grounded (use ohm meter to test that),,,,,,,,,or the points may have a
shorted spring.

5b) If the lamp never goes off as engines cranked, the points are not closing or are bad,,,,,,,,or the wire or circuit is missing from the
distributor to the points,,,,,or the distributors not well grounded to the tractor.

She cant fire the coil unless its low side is getting a conductive ground return path via closed points and then the circuit is open when
the points open.

Be sure the condensor or its wiring is NOT shorted out and see if the lite comes on (when points open) with the condensor disconnected. If
removing the condensor makes her spark, replace the condensor.

SUMMARY

Be sure the points are closing fully and open on high cam and ARE NOT BURNED OR PITTED OR CARBONED UP BADLY,,,,,,,theres voltage present on
distributors high side at all times when ignitions on (or its a bad switch or open ballast or bad wiring to col),,,,,,,voltage on coils low
side flashes on and off as distributor is cranked,,,,,,,,,condensors not bad/shorted,,,,,,,,no shorts in wires to points and no shorts in
pass thru side out distributor stud,,,,,,,,coil has continuituy.

You may luck out n just need a new set of points. If the coil wire fires (see above) and the plug wire ends to 1/8 from frame but NOT the
plugs, they are badddddddddddd. Check them BOTH.

John T

It is almost always the points. Start with the points. But clean up that blue connector on the coil too.

Try turning it over after dark while watching the coil. I fought with my old case for two days. It just so happened I was messing with it late one evening. As I cranked it, I watched a giant blue spark arc from the big coil wire down to one of the little terminals. It was not visible during the day. Changed the coil wire and fixed my problem.