IH Super C Electrical Woes

Thanks
Tom

YOU ARE CORRECT, as long as the coil gets sufficient voltage, she can still run regardless if the Gen works until the battery went like near completely dead.

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 dont 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 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 thats only a temporary cure, so if that cleaning makes her spark, INSTALL N GAP NEW POINTS.

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 ign 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 ign 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 attached to 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)

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 distributirs 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 baddddd ddddd . Check them BOTH.

Good Luck n God Bless, post back any questions and your findings and any questions.

John T in Indiana, retired electrical engineer.

Here's a step by step for troubleshooting for no spark:

Be sure distributor cap is dry & clean.
1. Is there battery voltage at the coil? Use test lite or volt meter.
2. Is there battery voltage at the points? Use
test lite or volt meter.
3. Remove distr. cap, rotor & points cover; remove coil wire from distr. cap & hold within 1/4" of a good ground.
4. With points closed and ignition switch on, snap the points open and closed a few times & check for spark at the coil wire end.
5. No spark: may have dirty or burnt points, bad condenser or coil. Coil wire must be attached to + on coil if battery is + grounded.

If this tractor has been converted to 12 volts and uses a ballast resistor they are known to cause problems. One last thing is to check for voltage at your ignition switch. Check for input voltage to the switch and with the switch on check
the output side for voltage. If you have voltage on the input side only, use a clip lead and jump
past the ignition switch and see if the engine will start. Hal

Thanks Again
Tom

But you all assume I understand basic testing.

I dont (but willing to learn)
You all say "with ignition on" Does that mean
pulling out the switch only, or should I also be
pulling on the starter switch (cranking) As for testing if coil is receive current: This is a 6 volt positive ground tractor. (OEM) dont think I have ballast/resistor.

As for testing if coil is receiveing current: I see a pos/negative connection on the back end.
where do I stick the voltmeter ends?--and again do
I just pull the ignition switch or crank as well when testing? Sorry being so ignorant, I never
received any electrical edumacation(but hey I know
computers pretty well? ;) )

Tom

Remove the cap from the distributor Two flat clips) near where the small wire (mentioned above) attaches.

Pull the coil "spark" wire out of the coil.

Pull #1 plug wire off of the #1 plug (closest to the radiator) and out of the distributor cap. (only remove one wire, it prevents confusion later)

Place a spare spark plug on the plug end of the wire just removed, and put the other end (that was in the cap) into the coil. rest the spark plug body on a metal surface where you can see its gap.

There may be a black/brown plastic disk under the cap, along with the rotor. Pull the rotor off (note it has a D shaped mounting hole to index it to the shaft) and remove the plastic disk if it has one.

Inside this next chamber are the points, consisting of a fixed contact screwed to the back plate, and a movable point arm with a contact on it matching the fixed contact. There is also a four lobed cam which rubs on and opens the points at the exact moment that spark is needed.

The condenser is also located inside, it is a metal can about an inch long and 9/16 diameter with a wire attached.

Tools needed a screw driver, and a dry popsickle stick or dry hard wood twig shaved to popsickel stick thickness and cleaned of bark.

Turn on the ignition by pulling out the button on the dash. (do not crank the engine)

Use the stick to open the points by pushing the movable arm in the direction away from the shaft.

If the points were closed, this action should produce a nice spark at the test spark plug. If it does not, the points may not have been fully closed. Next use the screwdriver, (holding only the plastic handle) place the metal blade at the points shorting the points to each other, then breaking the short by removing the driver. There should be a spark at the test plug if the points were open.

This process tests the condenser, and the coil.

the points should be cleaned with 220 paper, and gapped at .020" with the distributor four lobe cam pushing them their widest. Hand cranking the engine with the hand crank, or rocking the engine in high gear (with ign off) will position the cam on a lobe. (the lobe is just a rounded off portion of what looks like a square part of the distributor shaft).

The book is invaluble. Old cheap automotive text books are also very appropriate. Libraries have manuals in most cases that will apply.

Good luck, Email me if you want my phone # to talk you through it.
JimN

I took the negative wire off the stud on the input side of the coil (tractor is pos ground)
and with ignintion on, struck it against some bare metal on the tractor. I got plenty of spark.

So this tells me that juice is getting to the coil. I next disconnected the wire coming out the coil to the distrib and struck it against bare metal while cranking. No spark. Thinking
it might be bad wire, I took this wire off and substituted electric fencing wire. (had rubber gloves on.) Did the same thing with same results; no spark. So was this test done wrong or do I have a bad coil? BTW I just installed this coil new. (6V pos ground from TSC)