F40 no spark. No go.

[xfratboy]

Probably a dumb question but I'm stumped . '57 F40. 12v conversion to alternator. Entire fuel system redone including relined the gas tank. New carb from Amz. (Old one had a crack in the bowl). New fuel lines. New fuel bulb. I had some grounding issues causing starter solenoid intermittently to give a tink and then nothing would turn over. Fixed the grounding issue. Bypassed neutral safety (don't want it). Removed ammeter since it didn't work on 12v.

Now I'm not getting any spark when it turns over. It will crank all day long no problem. Thought maybe the coil was bad. No idea how old it was but it showed signs of being pretty old, so I replaced it with a new coil from Amz that had a resistor attached to it. When I turn key to 1st position and test the voltage at one end of the resistor I get 12.38 and almost 6v on the other side of the resister. I've pulled the center wire off the dist cap and held it 1/4" or closer to the block (or an any metal nearby) and it doesn't spark. I've inspected and even recrimped the end of the cable thinking maybe it was a bad cable. Still not getting any spark. 1.8ohm between + and neg posts of coil. 10k ohm from + post on coil to center of the coil (where the cable plugs into). What am I missing ? Maybe something inside the distributor is causing the problem? I feel like I've done a lot of just part swapping to no avail.

 

[stevieb49829]

Back in December, you had it running. What have you changed out since then? Do you understand how a distributor makes spark? Do you still have the points and condenser plate for the distributor or is it "in the landfill somewhere" too. Do you have voltage to the positive side of the coil when the key is cranking over the engine? The - side of the coil should be connected to the distributor, and the + side gets power in 2 positions on the start switch. You may be missing the circuit to the distributor on the second position of the ignition switch. That would indicate a bad switch, but check your voltage before you throw away the switch. steve

 

[xfratboy]

I wouldn't say I had it running in December. I think I fried the electronic ignition and the coil somehow back then. Mice got up in the tractor and nibbled through a bunch of wires. Saw sparks and smoke and the Pertronix sounded like it was sizzling inside... like a boiling sound... could have been the mouse issue or something I wired up wrong..I don't think there's a 'one way and one way only' rule to wiring a tractor but I may have done something wrong.. Anywho.... That's when I decided to swap back in the old points and condenser. If you've read through my posts you'll know I don't know what I'm doing, so not sure if that's a question or a jab? If I knew what I was doing I wouldn't need to ask questions to strangers on a forum.

 

[stevieb49829]

I wouldn't say I had it running in December. I think I fried the electronic ignition and the coil somehow back then. Mice got up in the tractor and nibbled through a bunch of wires. Saw sparks and smoke and the Pertronix sounded like it was sizzling inside... like a boiling sound... could have been the mouse issue or something I wired up wrong..I don't think there's a 'one way and one way only' rule to wiring a tractor but I may have done something wrong.. Anywho.... That's when I decided to swap back in the old points and condenser. If you've read through my posts you'll know I don't know what I'm doing, so not sure if that's a question or a jab? If I knew what I was doing I wouldn't need to ask questions to strangers on a forum.

It wasn't a jab. Several of us were trying to help you last fall. Just my way of saying you should track down the problem before you replace something. So, onward. Take a length of wire and hotwire from your + on the battery to the + side of the coil. (This assumes your system is negative ground, ie the - on the battery is connected to the chassis or engine on the tractor). Do you get spark at the center distributor wire now while the engine turns over? Then, check at each of the plug wires to a headbolt or even just stick a known good plug on the wire and lay it on the head. If you have good spark both ways, but still no spark without the hot wire, move your hotwire from the battery to the "I" terminal on the switch. Check again for spark. If no spark, there is something wrong with the switch, or the connections to and from the switch. If no spark with the hotwire to battery, you have a distributor problem. Could be just points adjustment, or could be a worn out distributor. Doing it this way, one step at a time will help you understand your wiring much better. Post a pic of the back of the switch, and we'll try to run down the problem from there. This does assume for right now you have the fuel problem fixed. Be careful the tractor is always out of gear. It could start and try to run you over. Don't ask me how I know that happens. steve

 

[Jim.ME]

I wouldn't say I had it running in December. I think I fried the electronic ignition and the coil somehow back then. Mice got up in the tractor and nibbled through a bunch of wires. Saw sparks and smoke and the Pertronix sounded like it was sizzling inside... like a boiling sound... could have been the mouse issue or something I wired up wrong..I don't think there's a 'one way and one way only' rule to wiring a tractor but I may have done something wrong.. Anywho.... That's when I decided to swap back in the old points and condenser. If you've read through my posts you'll know I don't know what I'm doing, so not sure if that's a question or a jab? If I knew what I was doing I wouldn't need to ask questions to strangers on a forum.

We area assuming your tractor is wired negative ground because you say it has an alternator. Please confirm your tractor is wired negative to ground (chassis), just to clear that point.

In addition to what stevieb49829 has suggested. Use a test light and see if you have power on the + (ignition) terminal of the coil when the ignition switch is on. If you don't follow stevieb49829 path. If you do have power, put the light on the - (distributor) terminal of the coil and crank the engine over. If the light doesn't flash on and off when cranking, the points are not opening, or there is a short to ground between the coil terminal and the points. If it stays on all the time, there is an open between the coil terminal and the points or the points, or distributor, are not making a ground.

Also, as a test you can use a jumper wire connected to the resistor terminals to bypass it when testing starting. Some systems using resistors do that automatically to get a better spark while cranking. If it starts you can remove the jumper and it should stay running.

 

[xfratboy]

Pics as requested. I've tried it this way and without the 2nd wire running to the coil. This is negative ground 12v converted with 1-wire alternator. When it is wired this way and the key is in the crank position, the starter keeps trying to engage. When I take the wire off that is running form the ST pole to the + of coil it cranks normal but still won't start. Probably doesn't make sense the way I'm explaining it. It was my understanding (and that is limited of course), that when the tractor is cranking (key turn turning all the way) it should send more voltage to the coil, but when you release he key the starter should stop trying to crank and voltage drops back to 6v.. When it is wired this way the starter keeps trying to crank. I'm wondering if this is indicating a bad key switch?

- 2 wires coming off the ST Post. One wire goes to small center post of starter solenoid. The other wire goes to output side of resistor (+ terminal of coil).
- IGN wire goes to input side of resistor.
- BATT wire goes to the starter solenoid on the same post as the battery cable.

 

[Brown David]

Removed ammeter since it didn't work on 12v.

????

 

[xfratboy]

We area assuming your tractor is wired negative ground because you say it has an alternator. Please confirm your tractor is wired negative to ground (chassis), just to clear that point.

In addition to what stevieb49829 has suggested. Use a test light and see if you have power on the + (ignition) terminal of the coil when the ignition switch is on. If you don't follow stevieb49829 path. If you do have power, put the light on the - (distributor) terminal of the coil and crank the engine over. If the light doesn't flash on and off when cranking, the points are not opening, or there is a short to ground between the coil terminal and the points. If it stays on all the time, there is an open between the coil terminal and the points or the points, or distributor, are not making a ground.

Also, as a test you can use a jumper wire connected to the resistor terminals to bypass it when testing starting. Some systems using resistors do that automatically to get a better spark while cranking. If it starts you can remove the jumper and it should stay running.

I don't have a test light but the voltage is now 12.38 anywhere in read it. + or Neg side of coil ... either side of the resistor. When I crank, the reading on the voltmeter errors out and gives -1 until I stop cranking and then returns to 12.3. Something is broke. Previously I was getting 12v on one side of resistor snd 6v on the other side.

 

[xfratboy]

What I thought I was doing and what I should be doing may be confused... followed this guy's diagram "I thought"

 

[Jim.ME]

I don't have a test light but the voltage is now 12.38 anywhere in read it. + or Neg side of coil ... either side of the resistor. When I crank, the reading on the voltmeter errors out and gives -1 until I stop cranking and then returns to 12.3. Something is broke. Previously I was getting 12v on one side of resistor snd 6v on the other side.

My personal opinion is, get a test light. They are cheap, usually less than 5 bucks for a decent one at Harbor Freight. They are good for quick power checks and for the test of the points I described.

If you are seeing the same voltage across the resistor and coil when the engine isn't running and the ignition switch is on, it sounds like the points are open or not conducting current if they are closed. When you put the points back in what did you set the gap at? Was the rubbing block of the contact arm on one of the high points on the distributor? Did you clean the points by rubbing a piece of brown paper bag, uncoated cardstock or even a folded-up dollar bill between the closed contacts?

The ammeter measures current, not voltage and doesn't know if it is hooked to 6 or 12 volts. If the ammeter was any good to start with it would work on 12 volts. It would read backwards if the wires were not swapped to the opposite terminals of the ammeter when the tractor was converted from positive ground to negative ground.

Do you have a manual for your tractor?

 

[Jim.ME]

What I thought I was doing and what I should be doing may be confused... followed this guy's diagram "I thought"

View attachment 66145

If you followed that diagram, it should work.

Too bad when you replaced the coil you did not get a true 12 volt coil (Standard Motor Products # UC15, NAPA #IC14 are a couple) and eliminated the ballast resistor and the 6 volt coil.

 

[stevieb49829]

Ok, to simplify things, take the ballast resistor out of the system temporarily. Then your IGN terminal on the switch goes directly to the + side of the coil. Disconnect the "I" wire at the solenoid, but make sure your switch still triggers your starter after you do that. Then disconnect the "S" wire on the solenoid so the starter does not engage.

If everything in the distributor is working right, your voltage should stop and start based on whether the points are closed or not. When the points close (the pad on the points drops onto one of the flats of the distributor cam) it causes a "short" directly to ground inside the distributor. The next part I don't understand very well, but that short, as the points close, collapses the field inside the coil, and the coil fires a spark through the center wire onto the distributor. Then the rotor in the distributor takes that spark to the different contacts, via the rotor, out through the sparkplug wires, one at a time, as it rotates. Working back through that scenario, you have to have voltage on both sides of the coil. The coil itself imparts some resistance to the electricity going through it, so it should be close to battery voltage on the + side of the coil, and somewhat lower on the distributor side of the coil. Then when you close the points, the voltage shorts to ground, and should go to zero on your voltmeter.

A simple test light works better to check this. Simply solder a couple of wires onto a 12V bulb, and use it to check when and where your 12v stops. Attach one end to a good ground and keep it there, then use the other wire as a probe to follow your 12 Volts through the system. Switch in the off position. 12 volts at the BAT terminal on the switch(check), turn switch on, 12V at the IGN terminal on the switch (check), turn switch to start, do you still have 12 Volts to the IGN terminal on the switch (check). With the switch still in the on position, 12 volts at the + side of the coil (check), about 12 volts on the - side of the coil. If that doesn't check, then pull the cap off the distributor, and assure that the points are "open". You may have to bump the engine a bit to get your points in an open position. If you can light up your test light all the way to the - side of the coil with the ignition switch in the start position, the next test is for the distributor and points. The Ballast resistor is not necessary to test the system. It's there to protect your points and coil over time.

You can do this points and distributor check first, because then all the rest of the tests above will not be influenced by your points. Reconnect the "S" wire on the solenoid. To test the points, your test light should be on with ignition on and the points open, and every time your points close, your test light should blink. So it should blink on and off as the engine spins. If it does that, but you still have no spark to any of the towers on the distributor, you need to carefully inspect your rotor and the cap for cracks or breakage. If nothing is obvious, disconnect the distributor from the coil (-) side and check continuity from that light gauge distributor wire to ground. It should show infinite ohms when the points are open, and hardly any ohms when the points are closed. If that's not true, you will have to do some very detailed inspection for where the short is in your distributor. Steve

 

[xfratboy]

I don't quiet understand the ballast resistor and wether or not I damaged it or the coil.. or if it's just a ticking time bomb...but regardless... IM A FREAKING IDIOT....Had the dang firing order wrong, ie wires plugged in the wrong order. Fixed that and everything seemed to be a lot better...go figure !
- removed the 2nd wire from the key switch that was attached to the center post of the key (labeled ST). In the diagram I posted earlier, this would be the green wire connected to the solenoid. Regardless of that diagram, if I wire it like that it does not work. I also only have a 3 post solenoid not a 4 post so I assumed I could just got from the center post of the key to the output end of resistor, but that didn't work. So that's out of the equation completely now.
- checked and doubled checked points. Gap was rechecked with feeler gage and set to .022.
- checked and cleaned plugs. Verified gaps around .025 for plug
- removed and cleaned any corrosion or crud on plug wire ends.
- reconnected the battery ... and it started right up like there was never anything wrong with it. I just ran the mower for the past 1.5hrs and didn't have a problem one. Somehow in the parts swapping and changing things out from electronic ignition back to points and condenser, I guess I just got my plug wires crossed.
(oh... I also got the timing light out and timed it to around 6 before TDC).

 

[Jim.ME]

I don't quiet understand the ballast resistor and wether or not I damaged it or the coil.. or if it's just a ticking time bomb...but regardless... IM A FREAKING IDIOT....Had the dang firing order wrong, ie wires plugged in the wrong order. Fixed that and everything seemed to be a lot better...go figure !
- removed the 2nd wire from the key switch that was attached to the center post of the key (labeled ST). In the diagram I posted earlier, this would be the green wire connected to the solenoid. Regardless of that diagram, if I wire it like that it does not work. I also only have a 3 post solenoid not a 4 post so I assumed I could just got from the center post of the key to the output end of resistor, but that didn't work. So that's out of the equation completely now.
- checked and doubled checked points. Gap was rechecked with feeler gage and set to .022.
- checked and cleaned plugs. Verified gaps around .025 for plug
- removed and cleaned any corrosion or crud on plug wire ends.
- reconnected the battery ... and it started right up like there was never anything wrong with it. I just ran the mower for the past 1.5hrs and didn't have a problem one. Somehow in the parts swapping and changing things out from electronic ignition back to points and condenser, I guess I just got my plug wires crossed.
(oh... I also got the timing light out and timed it to around 6 before TDC).

Glad to hear you got it running. Always check the simple things, it is easy to cross a couple wires, happens more than some will admit.

It is a good habit to get into of cleaning the point contacts with paper, once they are set, as I mentioned. Oil or dirt from a feeler blade can contaminate them and shorten the life of the contacts.

 

[stevieb49829]

Jim picked up on something I got wrong: "When the points close the current flows through the coil primary windings creating the magnetic field. When the points open the magnetic field collapses and induces the high-tension current in the secondary windings which flows to the distributor then out to the plugs, to create the spark."

I don't quiet understand the ballast resistor and wether or not I damaged it or the coil.. or if it's just a ticking time bomb...but regardless... IM A FREAKING IDIOT....Had the dang firing order wrong, ie wires plugged in the wrong order. Fixed that and everything seemed to be a lot better...go figure !
- removed the 2nd wire from the key switch that was attached to the center post of the key (labeled ST). In the diagram I posted earlier, this would be the green wire connected to the solenoid. Regardless of that diagram, if I wire it like that it does not work. I also only have a 3 post solenoid not a 4 post so I assumed I could just got from the center post of the key to the output end of resistor, but that didn't work. So that's out of the equation completely now.
- checked and doubled checked points. Gap was rechecked with feeler gage and set to .022.
- checked and cleaned plugs. Verified gaps around .025 for plug
- removed and cleaned any corrosion or crud on plug wire ends.
- reconnected the battery ... and it started right up like there was never anything wrong with it. I just ran the mower for the past 1.5hrs and didn't have a problem one. Somehow in the parts swapping and changing things out from electronic ignition back to points and condenser, I guess I just got my plug wires crossed.
(oh... I also got the timing light out and timed it to around 6 before TDC).

Thanks, Jim. And thanks for thinking I might be thin skinned. The way we work together on these, the OP will get the right info, in spite of me having some of it wrong. I'm OK with anyone correcting my mistakes.

Ain't it great when it all comes together? Glad to hear it is running. Now you can figure out if you need the ballast resistor. Check your coil. If it says it's a 12V coil, you are unlikely to need the resistor. Some even state on them "no resistor needed". With a 3 contact solenoid it would be up to your ignition switch to make the circuit for the resistor, or you can wire to the starter side of the solenoid. That wire would go directly to the coil, and the one from the ignition would go to the resistor and then onto the coil. steve

 

[Jim.ME]

Jim picked up on something I got wrong: "When the points close the current flows through the coil primary windings creating the magnetic field. When the points open the magnetic field collapses and induces the high-tension current in the secondary windings which flows to the distributor then out to the plugs, to create the spark."


Thanks, Jim. And thanks for thinking I might be thin skinned. The way we work together on these, the OP will get the right info, in spite of me having some of it wrong. I'm OK with anyone correcting my mistakes.

Ain't it great when it all comes together? Glad to hear it is running. Now you can figure out if you need the ballast resistor. Check your coil. If it says it's a 12V coil, you are unlikely to need the resistor. Some even state on them "no resistor needed". With a 3 contact solenoid it would be up to your ignition switch to make the circuit for the resistor, or you can wire to the starter side of the solenoid. That wire would go directly to the coil, and the one from the ignition would go to the resistor and then onto the coil. steve

From what he posted I expect he got one of the coils they advertise for 6/12 volt systems. They mount a ballast resistor on the mounting bracket of a 6-volt coil. On a 6-volt system the resistor can be removed, or simply bypassed. If being used on a 12-volt system, the resistor gets wired into the primary circuit ahead of the 6-volt. If he wants to get rid of the ballast resistor, he will need to purchase a true 12-volt coil, if I understood his post correctly.

 

[xfratboy]

From what he posted I expect he got one of the coils they advertise for 6/12 volt systems. They mount a ballast resistor on the mounting bracket of a 6-volt coil. On a 6-volt system the resistor can be removed, or simply bypassed. If being used on a 12-volt system, the resistor gets wired into the primary circuit ahead of the 6-volt. If he wants to get rid of the ballast resistor, he will need to purchase a true 12-volt coil, if I understood his post correctly.

Yes. It was one advertised at 6/12v with the ballast resistor on the side of the coil.