Enough battery for starting motor but not for spark?

So my Super C battery seems to have plenty enough juice left to run the starting motor, and it sounds like it is cranking normally. However, there does not appear to be any electricity going to the distributor. I tested the distributor coil wire and I do not think it is getting any electricity.

Could this be as simple as needing to charge the battery more? Could I jump the tractor with a car (it is a 12V battery system)?

It just seems strange that there is enough battery run the starting motor (and the headlights), but not for the distributor.

John

Do you have a test light? Start at the switch,check for power,work your way down.You may have a bad switch. You could have a wireing issue.Start at the top and work down.Find the spot where the power is lost.Check the points,they could be corroded/dirty. Yes you can jump 6 with 12. Except DO NOT hook directly to battery! Battery can explode! Instead,hook directly to starter lug,and to frame of tractor away from battery.And yes,a low battery with a heavy starter draw/drain can suck all the power from the ignition.

Do you have a hand crank for the tractor? When I suspect the battery (6 V ) is low on our C I just use the crank, usually
just a couple of pulls on the crank and it's running. If everything is correct it should start that easy. But, if your not
getting any voltage to the coil it will never start, you need to troubleshoot that before trying to start it, you will just
burn up the starter if you just keep trying. You could run a jumper wire to the coil to start the troubleshooting process,
and if that works then trace the circuit back to the battery.

The problem is VD while cranking . An undersized battery and or high reliance connections are the problem

Actually it's common. Just kinda hard to wrap your head around when you first hear about it. And I most likely will attempt to explain it poorly.

If say you need 150 AMPS to crank and engine and power the ignition system with the ignition pulling 10 AMPS. Once the battery pulls down under 150 AMPS available it shorts both the ignition and the starter motor. Say the battery is providing 140 AMPS. With the starter getting 135 instead of 140 you most likely won't even notice it. But with the ignition getting 5 AMPS, 50% of what's needed? Now you have a no start. And different ignition systems can be affected at different levels. 6 volt electronic conversions have a reputation of no start with very small voltage/amperage drops. Points and condenser seem to be more forgiving.

Rick

you probably have a resister in your wire going to the coil. put a voltage meter on the line to the resistor and it should read your voltage with the key turned on. then check the outlet wire to see if voltage I on it. voltage in but know voltage out means you need to replace it. if no voltage on inlet side then go backwards with your meter to find the problem. if you starter is turning your tractor over then it has enough voltage to start your tractor.

If you stick a voltmeter on the coils input (from ignition switch NOT to distributor) terminal and turn the ignition on there should be near battery voltage there..... HOWEVER If there's an inline series ballast resistor and a good set of points are closed it could be around 1/2 of battery voltage IE a set up with a 12 volt tractor and a 6 volt coil and series ballast

If the voltage on the coils input with ignition on is a lot less then battery voltage (or none at all) and if there's no inline series ballast resistor:

A) The ignition switch may be bad or resistive (burned or loose or corroded contacts)
B) The wires open or bad FROM battery source or ammeter TO ignition switches BAT Input
C) The wires bad or open FROM ignition switches IGN output TO coils input terminal.

Its possible to temporarily jump hot wire direct to the coils input to see if that fixes it

If you measure the voltage on the coils input while the engine is cranking over that can show if the starter is drawing excess current maybe dropping battery voltage too low. If it has a good battery ??? and the starter motor isn't bad ??? the coils input when cranking should be around 10 to 12 volts, if too low the spark may be weak possibly caused by a weak battery or a bad starter or else a bad loose resistive connection like a battery or ground cable or part of the ignition wiring.

A test lamp over on the coils other output (to distributor) terminal with engine slowly cranking over should flash ON when points are open but go OFF when they are closed.

Check voltage on coils input with ignition ON both when setting and when cranking then check wires and connections. Its free n easy to have a shop due a load test on the battery. Maybe its a bad battery ??? or a bad battery or ground cable ???

If all else fails work through my Test Procedure linked below

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


John T
John Ts Ignition

This is why you could get the engine to "pop" when first trying to crank it. The ignition switch was turned on and the coil
became energized while voltage was still relatively high. Then the first time the points opened when cranking, the coil fired
but then the voltage was insufficient to make a strong spark.

Beagle

P.S.-- I like magneto's

My brother's 101 was doing that after we brought it back from the dead. Crank all you wanted to no avail. Pull it 2 feet and it fired right up. Our auto-electric cousin told us to add a solenoid to fix it. gm

Read the other replys. My two cents. Did you clean the points first? After that
dive into the other replys.

Another possible - are the points gapped right to get enough spark? Might try setting them closer to the distributor cam so they will open a little more.

See if it fires when you let off the button, that is usually indicative of this issue.

Ok, I will try to clarify some things.

My battery on the tractor is a 12V, my super C has been converted to 12 volt so that simplifies the jumping with a car. Anything special with jumping a tractor or just connect the jumper cables directly to the 12V battery?

I have not cleaned the points yet or checked how close they are, but considering that the distributor is not even getting any electricity, based on my test, I would think that would not matter. However, I will certainly check that.

I do not have any sort of test light or voltage meter, but I should probably buy those just to have. I think I will buy a voltage meter and test light today.

However, first things first, I will fill the gas tank up to the top, try to start it one more time, then try jumping the battery. If that does not work, I will do some further troubleshoot.

(quoted from post at 10:34:27 04/01/19) See if it fires when you let off the button, that is usually indicative of this issue.

Click to expand...

I am not sure what you mean by this. I thought I heard it fire a couple times, for only a split second when I had the throttle higher up and used the starter, but it immediately died.

Filling the gas tank up to the top has nothing to do with your problem. Your tractor will start and run with <1 gallon of gas in it, if everything is working. It will not run with a 1000 gallon tank attached to it if there is no spark.

If you have no power to the coil, then you have a broken wire or a bad ignition switch. It's pretty simple.

While this is not a great way to go about testing for voltage, in the absence of a meter or test light, you can disconnect the wire from the coil, and tap it against a metal part of the tractor to see if you get a spark. Just tap once, tap quickly.

You can probably buy both test light and volt meter for under 20 bucks. However the test light is easiest to use. If you have power,the light lights up.12 to 12 is OK,but still safer to hook to starter and frame.But which ever you you do,always POSITIVE to POSITIVE;NEGATIVE to NEGATIVE. Doesn't matter if pos or neg ground.

Until you get a test light or a volt meter, you are just guessing, and possibly multiplying problems by making unnecessary changes.

If there is a Harbor Freight near you, they will have "decent" volt meters. The super cheap analog meters will work, but they don't hold up long. See if they have a mid price range. That is something you need to be able to trust, because somewhere down the line it will get used for checking voltage in the house or shop, your life kinda depends on it then.

A 12v test light is also very handy, quick checks, it will catch points making and breaking when a meter won't.

If no Harbor Freight, try Walmart, Home Depot, Lowes. Avoid the auto supply or electrical supply, high prices.

(quoted from post at 11:01:46 04/01/19) Filling the gas tank up to the top has nothing to do with your problem. Your tractor will start and run with <1 gallon of gas in it, if everything is working. It will not run with a 1000 gallon tank attached to it if there is no spark.

If you have no power to the coil, then you have a broken wire or a bad ignition switch. It's pretty simple.

While this is not a great way to go about testing for voltage, in the absence of a meter or test light, you can disconnect the wire from the coil, and tap it against a metal part of the tractor to see if you get a spark. Just tap once, tap quickly.

Click to expand...

Thank you! Gas is probably not my issue, but someone from my last thread suggested that low gas levels could complicate the issue if there is not enough to feed from the tank properly, so I just wanted to eliminate that as a possibility.

My Super "C" would not start with the starter, although the starter turned the engine sufficiently. I used the hand crank and it started immediately. Why?? Bad Coil.
New coil, no more problems.

So if I have no power to the coil, that is not an issue of the battery not being charged enough, correct? If the battery is only half charged, the coil will still get some power, just not enough.

My questions probably seem pretty dumb, but I am very new to tractors, and at 18 years old, I do not have much mechanics experience.

Problem is more than likely one of two things. #1. When the starter is spinning, it is using/robbing all the juice
from battery and none going to the ignition. If this is the case, you should be able to charge battery, jump
start, or pull start. #2. It could possibly not be getting enough juice to ignition system for other reasons.
Frayed wire, bad connections, bad key switch, etc. This can be checked out with key on, starter not engaged with a
test light, or meters.

John, you ask

1) "So if I have no power to the coil, that is not an issue of the battery not being charged enough, correct?

NOT CORRECT you can still have what you call "power" to the coil HOWEVER if the battery is severely undercharged ORRRRRRRRR
the battery or ground cables are bad ORRRRRRRRR the ignition switch or its wiring is bad such that if the voltage on the
coil drops below say 9 or so volts on a 12 volt system or 4.5 or so on a 6 volt system THE LOW VOLTAGE CAN CAUSE A WEAK
SPARK

You need to put a voltmeter on the coils input (NOT to distributor) terminal and measure it with ignition on BOTH when setting then during cranking. It needs to be near same as battery voltage when setting and then not drop too much when cranking. If it drops excessive when cranking the problem is

A) Battery is low
B) Starter motor is bad
C) Battery or ground cables are bad/loose/resistive
D) Ignition switch is bad or theres a bad connection to or from Ignition switch to the coil

YOU HAVE TO READ THE VOLTAGE ON THE COIL WHEN SETTING AND CRANKING TO FIND THE PROBLEM NOT GUESS


2) If the battery is only half charged, the coil will still get some power, just not enough.

THATS POSSIBLE

ACTION ITEMS THEN REPORT BACK

Have the battery load tested for free at about any auto or battery shop
Insure the battery is full charged
Make sure battery cables and ground cables are all good
Test the voltage on the coils input BOTH when setting with ign on and when cranking

Were trying to help but we need voltage readings to help more NOT guesses

John T Retired Electrical Engineer

I cannot thank everyone enough for the valuable help! I will buy a voltage meter and go through the procedures outlined on this thread. I will post the results when I try some tests and try to get it running.

I appreciate your help.

Most likely to be a bad set of points that need to be repalced or clenaed. If the point do not conduce power then you will NEVER have a spark simple as that

(quoted from post at 11:13:38 04/01/19) My Super "C" would not start with the starter, although the starter turned the engine sufficiently. I used the hand crank and it started immediately. Why?? Bad Coil.
New coil, no more problems.

Click to expand...

So even with a bad coil the engine can run? How does that work? I am unfamiliar with the specifics of a tractor electrical system.

In your "test", how did you determine there was no fire? Have you taken the cap off and looked for moisture? Simple quick test -
Take off cap, take off rotor. Make sure points are closed. Take something and barely open the points several times and look for
spark there. You need something that wont conduct electricity.

Many times a coil will work when cold and after say 30 minutes stop working but coils are also almost bullet proof. Point on the other hand go bad out of the clear blue. Easy way to test the point is pull the distributor cap and dust cover then turn ti on and carefully open the point by hand. You should both here and see a spark when you open the point. No spark means bad points or bad wire or ignition switch. Another way you can test it is with a simple hot wire from teh battery ignition side to the ignition side of the coil. Touch the wire to the coil with the points close and ignition switch off you should see a spark if the points are good. Trouble shooting a tractor is very simple and takes just a few things like wire and knowledge of how to test things.

Dad had a DC Case that was like that. I got real good at getting off the starter at just the right point so she'd roll over on compression and give the distributor enough juice for a good spark.
AaronSEIA

(quoted from post at 12:57:18 04/01/19) In your "test", how did you determine there was no fire? Have you taken the cap off and looked for moisture? Simple quick test -
Take off cap, take off rotor. Make sure points are closed. Take something and barely open the points several times and look for
spark there. You need something that wont conduct electricity.

Click to expand...

For my test, I pulled the distributor coil wire (the one I posted a picture of in this thread and circled yellow), put the tip of it about 1/8 to 1/4 inch from a piece of metal on the tractor, then had someone pull the starter on the tractor and spin the starting motor (how I typically would start the tractor). There was no spark.

Check all your electrical connections get a volt
meter and check volts everywhere there?s a
connection or splice in the wire butt splices or any
crimp connection can have power on one side but
not on the other look for green corrosion


A simple circuit the red circles show some places
where power can be lost

My farmall C has a mag so battery voltage is not critical to make a spark. May want to find a mag.

Is your super C 6 or 12v?

If 12v are you using a 12v coil or a 6v coil with a ballast resistor?

Eliminate the easy stuff first. Have you replaced spark plug wires, plugs points, condenser, rotor and
cap? Measure battery's cranking voltage. Look for bad cable connections.

Answer my questions above and if you still are having problems I may have some other tips on how to
make a hotter spark when cranking.

If the coil isn't producing a spark it can NOT run

John T

(quoted from post at 15:40:02 04/01/19) My farmall C has a mag so battery voltage is not critical to make a spark. May want to find a mag.

Is your super C 6 or 12v?

If 12v are you using a 12v coil or a 6v coil with a ballast resistor?

Eliminate the easy stuff first. Have you replaced spark plug wires, plugs points, condenser, rotor and
cap? Measure battery's cranking voltage. Look for bad cable connections.

Answer my questions above and if you still are having problems I may have some other tips on how to
make a hotter spark when cranking.

Click to expand...

It is 12V. I am not home right now, but I am planning to do some more diagnostics tomorrow morning. I will look at the connections, and I am not sure if it is a 12v coil or a 6v coil with ballast resistor. I can post back here when I figure out what I have.

Thanks, John

If its not firing quit guessing and work through all my tips already posted below as well as my Ignition Troubleshooting


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.

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

John T
John Ts Ignition Troubleshooting

John T, thank you very much for your help. I am not going to do any more guessing until I do actual testing and troubleshooting. I am buying a voltage meter and a test light tomorrow, so I will work through the tips you posted and figure out what is wrong.

Once I have detmermined what is wrong, I will post what I find. Thank you all!

One more question. I was studying a wiring diagram for a 12V Farmall with alternator, and there is a wire running from the alternator to the ignition switch, as well as a wire running to the ignition switch from the ammeter. Why are there two wires to the ignition switch and which to test?

The small wire from the ignition switch to the alternator probably has a 10 ohm resistor, or a 3 amp diode in it
some where. (taped into the wire) This wire provides exciting voltage to the internal regulator of the alternator,
turning it on. The resistor, or diode, prevents flow of current from a charging alternator from keeping the engine
running when the ignition switch is shut off. The bigger wire goes to the amp meter to flow into the battery to
charge it. The key gets its electricity from that same terminal on the amp meter. Jim

You're sure welcome, work through my troubleshooting step by step and you should find the problem. Glad to be of help

John T

Thanks everyone! As soon as I run through the troubleshooting I will post what I find.