Super C problems STILL

Before anyone jumps down my throat you have to know this is the first time I have replaced a coil, a set of points condenser. All this is new to me so please be gentle.
I wrote before about a bad coil.

Ok, I replaced the coil that I thought was bad. The new coil I got was from the local IH dealer. I asked if it was 6v or 12v and they said this one was the same. OK?
On the old 6v coil the wire from the resister went to the negative post and the wire to the distributor was the positive post. That is how I wired the new one. Well when I pulled the coil wire off the distributor cap and cranked it the coil wire was HOT. So I plugged it back in. I pulled a spark plug and held it to metal and cranked it. I got nothing until I let off the starter and then it would lightly spark once. I decided to install new points and condenser. So I installed them and gapped the points at .020 and put everything together. I still got the same spark at the plug. Nothing as it was cranking but a slight spark as it stopped. I read on a thread somewhere here that the wire from the resister needed to be on the positive and the wire to the distributor was the negative. So I switched them and tried it. I am getting faint spark now but not enough to start.
I tested how much power I have at the coil.With the points closed I have 6.2v. When I open the points I have 12.4 volts. I don’t know why I have 12.4 with them open because I have a resister?
Anyway the tractor will not fire. I am thinking that all I haven’t changed is the cap, rotor, and wires. I am about to change the cap and rotor to see what happens. Anyone got any Ideas? Please be kind I am a newby at this. Ron

Technically they are (6v-12v) interchangeable, BUT a 12v coil will generally have a stamp on it that says "internal resistor"...or not...now in a 12v application I know that if it doesn"t say that you have to use an external resistor. I have never used a coil labled 12v on any of our 6v tractors so I don"t know, but I would assume that you would need to uses resistance in that application regardless.

Coil's can be 6v, 12 volt needing external resistence or 12v with internal resistence. You need to verify what you have.

As a test bypass the resister and see if it fires.

On a 12v neg ground system the power goes to the + side of the coil then to the distributor.

What is the history on your SC? Did it run before and fail? Did you buy it not running?

Sounds to me like you have high resistance through the cap/rotor. If you have a hot spark from the coil, then you are losing it somewhere between the cap and the plugs. I have had rotors with a very small hole burned through them. The spark would jump through the hole to the distributor shaft- the path of least resistance. Could also be poor contact between the cap's center post and the rotor, or a cracked cap or carbon tracking inside the cap causing the spark to jump to ground instead of going to the plugs. This is all assuming that your plugs and wires are good and you have a good spark- bright and blue. Just a few things I've come accross over the last 20-some years of wrenching for a living.

in my prior post I was reading as if by coil wire you meant the coil secondary wire had a hot spark. Or did you mean the primary wire between the coil and distributor physically gets hot?

(quoted from post at 01:14:02 12/14/10)

......I tested how much power I have at the coil.With the points closed I have 6.2v. When I open the points I have 12.4 volts. I don’t know why I have 12.4 with them open because I have a resister?..... Ron

Click to expand...

With the points closed you have a complete electrical circuit that has two resistance units, the resister and the coil. In your case the resistance value is the same for both as shown by having 1/2 circuit voltage between the resistance units. Each unit will draw 1/2 the total amperage of the system. With the points open the circuit is no longer complete. There will be no amperage draw in that circuit. The circuit still has electrical potential of 12.4 volts. Coming from the battery the voltage will be battery voltage up to the point where the circuit is open. From the break in the circuit back to the battery the voltage will be zero.

"I got nothing until I let off the starter and then it would lightly spark once".

When you are cranking the engine should get full voltage to the coil from the starter solenoid and once it starts to fire and the starter stops it should fall back to about half voltage to the coil. I suspect the problem is in the starter solenoid ignition start circuit.

I could be all wrong so this is a free idea.

Place a voltmeter on the coil voltage supply wire and watch the voltage during cranking. The supply voltage should be high during cranking and then drop back once it is running. There cold be a problem with either the starter solenoid or the ignition switch that won't allow the high voltage during cranking.

There is no solenoid on the C unless he or someone has put one on. The way he talks something is strange.

You dont have the original system so what all has been changed as you must have a 12v battery so what else is not original. Your problams are strange.

Lets go back & ask if this unit was running before you changed the coil. Probably wasn't since that is why you changed the coil. Had you changed the points/ condenser at any time prior to the engine not running? Did you take the distributor out before changing the coil? Let us know.

My 100 is on 6 volts, so no comment on the 12 volt part of the problem,
but
as I put the tractor back together, it wouldn"t start, and the coil got hot. So hot I thought I had ruined it.

The problem was I had wired it "backwards" --- mine is still set to + ground, and I connected the wires wrong. I just flipped the coil over and swapped the wires. Even though it got hot, it wasn"t ruined, and is still running today.

I didn"t see any other response address the +- ground issue on 12 volts. Maybe someone more knowledgable than I can address this issue ?

All ignition systems will spark once when the key (ign sw) is turned off and to a lesser extent on) this is because the switch acts like a set of points in the series circuit. Having the plug wire fire just as you stop cranking it is not a consistant thing due to the rotor pointing to different spark plugs at different times of the rotation.
The coil needs to be attached to the electrical system in the same polarity as the battary. If the battary and charging system are Positive ground (original 6 volt, and usual with 12 volt generators if using standard Delco 12v generators and regulators from 12v Farmalls) the coil should be negative to the distributor, and positive to the ignition switch. Make sure of the batt ground polarity.

Volt meters will read open circuit voltage (points open) at full bat voltage, even with the resistor in the circuit. The voltage on the distributor terminal from the coil should change from 12+ volts with the points open, to nothing with them closed (measured from ground to the terminal with the meter set on 20 volts, not cranking) if this does not happen, there is a problem in the distributor/points connections internal to the distributor.

A simple check to determine if the system is not getting enough voltage to fire when cranking is to use a separate battery to give it ignition voltage temporarily. Just use a 12v battery and a few feet of 12ga wire to connect the battery to ground (same polarity as the installed battery). Then disconnect the ballast resistor on the side away from the coil, and connect the other lead to that side of the ballast resistor. This provides a complete separate ignition source, so do not leave it connected unless you are actively working on the tractor. Make the connections so that they can be removed, as the removal will shut off the tractor if it starts.
If the tractor starts now, My suspicion is that the battery voltage on the installed battery is dropping during starting such that there is not enough to make it start. Get back to us. Jim

The wiring for the coil on a 12V negative ground system:

1. ignition switch-->ballast resistor--> + terminal on coil
2. - terminal on coil --> terminal on side of distributor

If you do it backwards you will get a weak spark.

But you said the spark from the coil was HOT, right?

Replace the cap and rotor.

Hi Idaho Ron...A lot of these old tractors have been converted from 6 volt positive ground to 12 volt negative ground. So as I read your post I was trying to find a clue as which setup your tractor has. But I got conflicting clues and couldn't tell for sure. But you did say you got 12.2 volts so you must have a 12 volt battery in it and it probably (??) is negative ground also. The grounding setup determines how the coil is wired and your original wiring seemed like it was wired wrong because it was wired for a positive ground system. Yet if you have a 12 volt system and these were almost always negative ground. So check that out.
When you bought the coil the dealer probably didn't know you had the tractor converted from the original 6 volt system to 12 volts so he may have sold you the original type 6 volt coil. I'd check with the dealer and see exactly what you got. If you have a 6 volt coil with a resistor in front of it, that could be your faint spark problem.
Pete

You should use a resistor with a 6v coil. I would make sure those points are really clean & gapped right.

The tractor was running about two weeks ago. I was plowing snow and after it warmed up it was bogging down when I used the hydraulics or when I let out the clutch. I took off the gas bowl and cleaned the screen and drained a little gas out to check for water. I took out the screen in the carb and checked it. When I turned the gas back on gas poured out of the carb So I figured the carb needed rebuilt. I took it to a shop to be rebuilt. When I got it back I put it on and gave it a try. The battery was weak so I hooked it to the charger on boost. That is when the coil got hot and leaked oil.
The tractor has a 1 a wire 12v alternator and a 12v battery. I have a resister behind the dash that drops the voltage to 6.2 volts to the coil. This system has been working for the last 4 years. The starter is original. The distributor was NOT taken out at any time.
I added a new coil, and took the coil wire off the distributor cap. I got good HOT spark there. I plugged it back in.
With the points closed I have 6.2 volts at the + post. With the points open I have 12.4.
I put in brand new points and they are set at .020
Thanks for helping guys. Ron

IF there is a strong, blue spark at the coil wire and not at the spark plugs, the cap &/or rotor are suspect as well as the plug wires.
Follow the spark.

Like Wayne said, Follow the spark. Did the cap get wet when you were plowing snow? Your problem is the cap or rotor or both. All 4 wires don't fail at once.

Our power was out for about 4 hours so I didn't get a chance to get a new cap and rotor. I did clean the contacts and the rotor better but they are well worn. The spark at the plugs looks weak but I did get the tractor to pop a few times. I am encouraged that a new cap and rotor will get her to go. I will find out tomorrow. Ron

I personally think that you're on the right track. If the spark from the coil is good, and now you are getting some spark at the plugs after cleaaning the cap and rotor, then I would think a new cap and rotor will do the trick. Best of luck and let us know the outcome!!

You have a bad switch.

Did you ever find the true source of the problem?

Yes I posted it the next day I think. Sounds like you missed it. The guys that said it was a bad cap and rotor were right. My coil was fried so I put on a new one. I wired it backwards so I switched the wires so the – went to the distributor. I was getting spark but not much at all. It would pop a little as I let off the starter switch. So I switched the cap and rotor and it fired up before it turned over twice. Ron