Voltage to Coil

[mustangmarty]

How many volts should be coming off of the R-terminal from the starter to the ballast resistor that mounts on top of the coil of an IH 2444 with a gas engine? Mine shows about 8 volts with the key in the run position. Once in a while, it will show 12 volts as I push the start button, but usually only still shows about 8 volts. I have no spark. The ballast resistor and the coil together show about 5 ohms resistance across the posts, and the coil plug to post resistance shows about 12,000 ohms, so I think they are okay. Its a new coil and resistor block. There is no loss of voltage from the ceramic resistor block back to the R-terminal on the starter.

 

[John T]

With the points OPEN and Ignition switch ON, the voltage at the ballast resistor INPUT, its OUTPUT, and at the coils INPUT should be the same as the batteries voltage around 12 on a 12 volt tractor.

With the points CLOSED and if they are good and non resistive..

With Ignition ON the voltage on the ballast resistors INPUT would be near battery voltage,,,,,Voltage on ballast resistors OUTPUT and to coils INPUT would be in the 6 to 7/8 volt range. The ballast drops the 12 battery volts down to 6 or so for a 6 volt coil

This assumes its a 12 volt tractor with a ballast and a 6 volt coil

NOTE if it has the start ballast by pass system when cranking theres unballasted battery voltage (around 12) to the coil as the ballast and its voltage drop is out of the circuit this is to improve cold weather starting...

To find the casue of no spark work through my Troubleshooting Procedure

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

John T
John Ts Ignition Troubleshooting

 

[Janicholson]

Go with John T's link. The Resistor bypass should not have battery volts on it unless the starter is turning, and then it should be at about 10.5 to 11.5 volts based on starter draw. So that 8 volts you found there would be correct with the key on and points closed. you are seeing the voltage on the coil side of the ballast resistor, not any voltage coming out of the starter solenoid. jim

 

[Jim Becker]

Marty's 8 volt reading strikes me as in agreement with having a 12-volt "no external ballast required" coil in a "ballast required" circuit. Recheck that you have the right type coil.

The sometimes 8 volt, sometimes 12 volt reading suggests a poor contact inside the solenoid. The solenoid may need replacing.

Both of these potential problems could make for a poor spark. But I doubt that either by itself is enough to get no spark. I'd check the new coil for proper version. Then follow the troubleshooting link.

 

[Jim.ME]

Unhook the wire from the R terminal on the starter and I think you will see the 8 volts is on the wire from the coil when the key is on. There should be no voltage showing on the R terminal with the key in the run position. The R terminal should only have output voltage when the solenoid/starter is engaged. It is intended to provide a full voltage bypass of the ballast resistor ahead of the coil [u:1648a1905b]only during starting.[/u:1648a1905b] The wire from the R terminal should go directly to the coil terminal that the wire from the ballast resistor hooks to.

This post was edited by Jim.ME on 02/21/2022 at 11:14 am.

 

[mustangmarty]

The resistance across the ballast resistor is 1.5 ohms and the resistance across the (+) and (-) coil terminals is 1.9 ohms. The resistance from the ballast resistor input terminal to the (-) terminal on the coil is 3.5 ohms. The circuit light tester flashes when the I crank the starter. The points look good and are gapped at .020. A continuity test shows good continuity from the spark plug seats in the head all the way to the points, condenser, and distributor plate. There is absolutely no spark when I crank it over with the coil wire plugged into the coil and the other end held 1/8 from the engine block. The + terminal of the coil has only one wire connected to it that goes to the output of the ballast resistor, and the input side of the ballast resistor has only one wire going from it to the R-terminal of the starter. Should there be another wire coming off the input side of the ballast resistor going somewhere else, and where should it go? Should I have another wire coming off the (+) terminal off the coil, and where would it run to? I have about 8 volts at the ballast resistor input with the key in the run position all the time and most of the time when the starter is cranking. Every once in awhile it will have about 12 volts during cranking, but not very often. Its always ran fine before. Though its been about six months now since it ran last. It will be Saturday before I get another chance to fart with it. Next step I guess is to run a wire directly from the battery to the input side of the ballast resistor since I have a 6-volt coil. I would think going directly from the battery to the coil might damage the coil. Is that correct? I will also try removing the condenser in case I got a defective one from the parts house and see what that does. For what its worth, the coil, coil wire, plug wires, cap, rotor, condenser, and points are all relatively new. And by relatively new, I mean only a year or two old.

 

[mustangmarty]

Forgot too add that I will likely be replacing the solenoid on the starter, but I dont know the manufacture date. I only know its somewhere between 1967 to 1971. The serial number is 02774. Can anyone tell me the year of this tractor, or at least the correct part number for the solenoid and the best place to get one from?

 

[Jim.ME]

Is it a Delco starter? Is the tag still on the starter? That is all you should need to get a solenoid. In fact, it is likely even without tag numbers you can just take the old solenoid in, and a parts store will have one on the shelf to match it. Many Delco starters, in different applications, used the same solenoid. I have done that many times for equipment. Try a 1978 chevy pickup if they want a vehicle.

 

[rvirgil_KS]

The + terminal of the coil has only one wire connected to it that goes to the output of the ballast resistor, and the input side of the ballast resistor has only one wire going from it to the R-terminal of the starter. Should there be another wire coming off the input side of the ballast resistor going somewhere else, and where should it go? Should I have another wire coming off the (+) terminal off the coil, and where would it run to?

There should be a wire from + terminal on the coil to output of the resistor
There should be a wire from input of the resistor to the ignition on/off switch.
The wire from the R terminal on the starter solenoid to either end of the + coil/resistor output wire.

When running the resistor drops voltage to about 6 volts for 6 volt coil, and current to the designed 4 amps normal operation. When the starter is activated, the solenoid R terminal supplies 12 volts to + on coil, thus bypassing the resistor, to give a hotter spark for starting. When starter is released + terminal on coil goes back to normal operation.

Here is a diagram to illustrate, may not be exact but will show the operation. S on solenoid is the start activation connection. I (ignition) of diagram or R (resistor) on your solenoid shows that solenoids may be marked differently.

 

[Jim Becker]

"The + terminal of the coil has only one wire connected to it that goes to the output of the ballast resistor, "

As stated, there should be another wire from the solenoid to one end or the other of this wire. If that wire disappears into the wiring harness, it could have a wire from the solenoid spliced at some point in the wire. Also beware that the wire that should go from the ignition switch to the resistor, may go by way of a junction block.

 

[mustangmarty]

Thank you rvirgil_KS for that schematic. I would like to bench test my solenoid separate from the starter. I was thinking of using a battery and jumper cables and connecting the positive clamp to the main post on the solenoid and connecting the negative clamp to the metal casing. Then connect a 10 gauge jumper wire from the S terminal to the metal casing with alligator clips. Then connect a voltage meter via alligator clips to the casing (negative lead) and to the R terminal (positive lead). Then connect another 10 gauge jumper wire to the R terminal and then touch the other end to the metal casing momentarily only and watch the meter. If Im not mistaken, I would think I should see zero voltage until I touch the jumper wire from the R terminal to the casing, at which point I should instantly see 12 volts. How does this sound? My only real worry is what will the open end of the solenoid do where the spring was.

This post was edited by mustangmarty on 02/28/2022 at 07:06 pm.

 

[Jim.ME]

(quoted from post at 23:03:27 02/28/22) Thank you rvirgil_KS for that schematic. I would like to bench test my solenoid separate from the starter. I was thinking of using a battery and jumper cables and connecting the positive clamp to the main post on the solenoid and connecting the negative clamp to the metal casing. Then connect a 10 gauge jumper wire from the S terminal to the metal casing with alligator clips. Then connect a voltage meter via alligator clips to the casing (negative lead) and to the R terminal (positive lead). Then connect another 10 gauge jumper wire to the R terminal and then touch the other end to the metal casing momentarily only and watch the meter. If Im not mistaken, I would think I should see zero voltage until I touch the jumper wire from the R terminal to the casing, at which point I should instantly see 12 volts. How does this sound? My only real worry is what will the open end of the solenoid do where the spring was.

This post was edited by mustangmarty on 02/28/2022 at 07:06 pm.

The open end of the solenoid will do nothing. And unless I am mistaken you won't get the readings you want because the plunger isn't there to pull in and push the rod, connected to the copper disc in the contact area, ahead to make contact between the battery terminal, the R terminal, and the terminal that connects to the starter motor. The S terminal being energizes the solenoid coil which is an electromagnet to pull the plunger in to operate the rest of the functions. No plunger, no work.

 

[mustangmarty]

Thank you rvigil_KS for that schematic. I would like to bench test my solenoid separate from the starter, since Ive already removed it and wont be near the tractor again for a few days. I was thinking of using a battery and jumper cables and connecting the positive clamp to the main post on the solenoid and connecting the negative clamp to the metal casing. Then connect a 10 gauge jumper wire from the S terminal to the metal casing with alligator clips. Then connect a voltage meter via alligator clips to the casing (negative lead) and to the R terminal (positive lead). Then connect another 10 gauge jumper wire to the R terminal and then touch the other end to the metal casing momentarily only and watch the meter. If Im not mistaken, I would think I should see zero voltage until I touch the jumper wire from the R terminal to the casing, at which point I should instantly see 12 volts. How does this sound? My only real worry is what will the open end of the solenoid do where the spring was.

 

[mustangmarty]

Ah. Didnt know that. Thank you for the solenoid lesson. I will
reinstall the solenoid, and check voltage on the R-terminal with
no wires connected to it.

 

[mustangmarty]

Finally got a chance to put the solenoid back on and do a voltage check on everything yesterday.

Key off:

12.8 volts at starter cable stud

0 volts everywhere else


Key in run position:

Starter cable stud - 12.8 volts

Starter motor stud - 0 volts

S terminal - 0 volts

R terminal - 0 volts

Ballast resistor input - 8 volts

Ballast resistor output - 4.9 volts

Coil input - 4.9 volts

Coil output - 1.73 volts


Start button being pressed:

Starter cable stud - 12.8 volts

S Terminal - 3.1 volts

R Terminal - 2.3 volts

Ballast Resistor Input - 2.75 volts

Ballast Resistor Output - 1.3 volts

Coil Input - 1.3 volts

Coil Output - 0.7 volts

I also noticed that the solenoid started making a humming noise when my helper was pushing the starter button.

 

[Jim.ME]

Would it be wise to start at the beginning again? We are deep in to the solenoid function here, but I think buried in your first post on this is the real issue: You posted you have no spark.

Start with some history. What are you working on? Was it running and just wouldn't start one day? Did you do some maintenance and change some components then it would not start. You posted it has a new coil and resistor block. In later post you say "the coil, coil wire, plug wires, cap, rotor, condenser, and points are all relatively new. And by relatively new, I mean only a year or two old."

Used points can be gapped however if there is pitting in one contact and material transfer build up on the other contact, the gap may not be correct. The specified gap is for smooth surface point contacts.

You have posted "The circuit light tester flashes when the I crank the starter." If this is a test light on the coil terminal with the wire going to the distributor, the points are working, and you should have some spark.

What is the voltage reading on the battery cable stud of the solenoid when the engine is being cranked over? What is the voltage across the battery terminals while the engine is being cranked over?

Try connecting a jumper wire from the battery to the coil, which will bypass the ignition switch, ballast resistor, solenoid R terminal and wiring related to them. Try cranking it and see if you have spark and it starts.

Do you have another coil wire to try in the coil?

 

[mustangmarty]

The last time it ran was July of last year. Then the Governor rod
disconnected from the throttle Rod. Took several months to get
to it. Once I fixed the Governor connection, it started right up
and ran fine. Then let it set a few months until I needed it again.
Then suddenly it had no spark.

The points are smooth, no pitting at all.

Battery cable stud on solenoid shows 12.8 volts with key on and
pushing starter button. Didnt specifically check across battery
terminals during cranking.

I will try running a jumper wire from positive battery cable to
either the coil or the ballast resistor. Im last of putting 12.8
bolts directly to the coil though. Im assuming that since it has
a ballast Resistor, that its a 6 volt coil, and I dont want to fry
the coil. I have tried another coil wire since the one on it is
relatively new and has been working before.

I went ahead and ordered a new solenoid since the R Terminal
on the one on it now has nowhere near the full voltage I believe
it should have during cranking.

 

[mustangmarty]

I have not tried another coil wire yet.

 

[Jim.ME]

(quoted from post at 17:53:14 03/06/22) The last time it ran was July of last year. Then the Governor rod
disconnected from the throttle Rod. Took several months to get
to it. Once I fixed the Governor connection, it started right up
and ran fine. Then let it set a few months until I needed it again.
Then suddenly it had no spark.

The points are smooth, no pitting at all.

Battery cable stud on solenoid shows 12.8 volts with key on and
pushing starter button. Didnt specifically check across battery
terminals during cranking.

I will try running a jumper wire from positive battery cable to
either the coil or the ballast resistor. Im last of putting 12.8
bolts directly to the coil though. Im assuming that since it has
a ballast Resistor, that its a 6 volt coil, and I dont want to fry
the coil. I have tried another coil wire since the one on it is
relatively new and has been working before.

I went ahead and ordered a new solenoid since the R Terminal
on the one on it now has nowhere near the full voltage I believe
it should have during cranking.

Fold a dollar bill up, put it between the point contacts while they are closed and rub it back and forth a few times to polish the surfaces, they can oxidize when setting.

To be clear when you say pushing the starter button, is the starter mounted and cranking the engine? Your battery and starter must be excellent if the voltage reads the same (12.8 volts), at the battery stud of the solenoid, if it shows no voltage difference between when not energized and when cranking the engine.

A jumper wire to the coil will not hurt for a start test. If connected and hooked up correctly, the wire from the R terminal of the solenoid does exactly that, bypasses the resistor and supplies applies full battery voltage directly to the coil for starting.

This post was edited by Jim.ME on 03/06/2022 at 02:57 pm.

 

[mustangmarty]

I ran a 10 gauge jumper wire from the positive terminal of the
battery to the ballast resistor input stud and still got no spark.
Then I switched it over to the ballast resistor output stud and I
got an orange-yellow spark. Plugged the coil wire back into the
distributor and she started right up. Then removed the jumper
wire, and it kept running fine. So looks like the replacement
starter solenoid should fix things. Its in the mail and should be
here Friday. I should be able to get it installed Saturday or
Sunday. Will update after that.

 

[mustangmarty]

Just replaced the starter solenoid and made sure all wires are in the same place. Now the starter starts bendix starts spinning as soon as I reconnect the battery. Key is off. Button not being pushed. Even with both the S stud and the R stud disconnected. It does the same thing. Im assuming my new solenoid is defective?

 

[mustangmarty]

Think I figured it out. The bendix spring that came with the new solenoid was too stout. I put the old spring in with the new solenoid, and its working now.

 

[Jim.ME]

Good you have it working, but that sounds strange. The spring goes inside the solenoid then the plunger fits inside of the spring. When power is removed from the solenoid (magnet) the spring pushes the plunger out to disengage the plunger from the contact pin to stop the starter and moves the drive out of the ring gear at the same time. If the spring was too strong it would prevent the plunger from pulling in to hit the contact pin and power the starter motor, as well as the drive wouldn't engage the ring gear. Sorry, but having it turn as soon as you connected the cables it sounds like the spring was on the wrong side of the plunger, forcing it in, causing the contacts to be closed. If not that, in tightening the battery side contact it rotated enough to contact and send power to the solenoid start terminal, then in changing the spring you moved it enough to break the connection. Pretty easy to twist the contacts in the plastic cap.

 

[mustangmarty]

Think I figured it out. The bendix spring that came with the new solenoid was too stout. I put the old spring in with the new solenoid, and its working now.

 

[mustangmarty]

On mine the plunger has a spring seat ring. The spring goes
between that spring seat and the solenoid while the plunger
goes inside the spring down into the cup/hole in the solenoid. It
seems like the plunger is supposed to stay pushed away from
the solenoid when not in use. It is connected to a lever down
inside the starter. In this position, the sprung lever keeps the
bendix pulled in toward the starter. Then when power is
supplied, Im assuming a magnet pulls the plunger in toward the
solenoid, which in turn levers the bendix inside the starter
outward toward the flywheel. Since the new spring was too
stout, the solenoid magnet couldnt overcome it and so the
bendix was spinning inside the starter without being levered into
the flywheel. Either that, or the magnet is too weak to
overcome the new spring. That still doesnt explain why the
bendix would start spinning without any power to the S terminal
though. Unless like you say, the main battery terminal is twisted
somehow inside the solenoid and making contact with the S
terminal inside the solenoid.

 

[Jim.ME]

(quoted from post at 09:50:43 03/14/22) On mine the plunger has a spring seat ring. The spring goes
between that spring seat and the solenoid while the plunger
goes inside the spring down into the cup/hole in the solenoid. It
seems like the plunger is supposed to stay pushed away from
the solenoid when not in use. It is connected to a lever down
inside the starter. In this position, the sprung lever keeps the
bendix pulled in toward the starter. Then when power is
supplied, Im assuming a magnet pulls the plunger in toward the
solenoid, which in turn levers the bendix inside the starter
outward toward the flywheel. Since the new spring was too
stout, the solenoid magnet couldnt overcome it and so the
bendix was spinning inside the starter without being levered into
the flywheel. Either that, or the magnet is too weak to
overcome the new spring. That still doesnt explain why the
bendix would start spinning without any power to the S terminal
though. Unless like you say, the main battery terminal is twisted
somehow inside the solenoid and making contact with the S
terminal inside the solenoid.

Yes, that is how the spring works. I still doubt the spring was the actual problem. Given what you have posted this time I would guess one or more of the solenoid studs twisted when you tightened things and contact was made between them which made the motor spin when the cables were hooked up (Or the lugs on the starter link and battery cable are big enough to touch each other if turned just right). Taking it apart when changing the spring broke the contact and when they were tightened after the spring change, the contact wasn't made as it did before. That unintentional contact could spin the starter motor, but not energize the solenoid to move the drive into the ring gear, exactly what you described.

 

[mustangmarty]

Makes sense. Im gonna return this one for a full refund. So
much for.