Spark issues

Trz

Member
1950 8n front dist. 6v. No spark to the plugs. Removed distributor did testing with multimeter, everything checks out there. With key ON I have 6.24v from battery ground to each of the three leads on the resistor. With key ON I havev6.24 v from battery ground to top of coil.
I tried jumping from pos. battery side to coil (when I first touched lead wire to bat. I got a little spark.) and it fired right up. Disconnected and it shut off, fine. Picked up my tools and tried jumping again so I could move the tractor up to the house and it wouldnot start or even fire, I couldn’t even get that little spark when I touch the jumper to the terminal.
I don’t know much about electrical systems so I’m just going by advise I’ve found on here. But, I’m lost as to what to do now.

Any advise would be appreciated. Thanks in advance.
 
1950 8n front dist. 6v. No spark to the plugs. Removed distributor did testing with multimeter, everything checks out there. With key ON I have 6.24v from battery ground to each of the three leads on the resistor. With key ON I havev6.24 v from battery ground to top of coil.
I tried jumping from pos. battery side to coil (when I first touched lead wire to bat. I got a little spark.) and it fired right up. Disconnected and it shut off, fine. Picked up my tools and tried jumping again so I could move the tractor up to the house and it wouldnot start or even fire, I couldn’t even get that little spark when I touch the jumper to the terminal.
I don’t know much about electrical systems so I’m just going by advise I’ve found on here. But, I’m lost as to what to do now.

Any advise would be appreciated. Thanks in advance.
Hot wired may have burn the point a bit so clean them. What you did says your problem is either the ignition switch or the resister or the wire
 
If that's not a typo, jumping from the positive side of the battery actually did nothing for you accept make a spark, assuming your 6 volt 8N is still positive ground. To bypass the ignition switch and ballast resister you need to jump from negative battery post to the top of the coil. However because that temporarily solved the problem, I would be looking at loose, or corroded connections anywhere in the circuit. Ignition switch, ballast resister top of the coil and under it and like Old said, points contacts. Either fouled or not making with enough tension.
You may be able to read battery voltage through a corroded or loose connection but it won't pass the current needed for the coil.
 
Hot wired may have burn the point a bit so clean them. What you did says your problem is either the ignition switch or the resister or the wire

so, my next question would be, how to diagnose which of those three things is the problem without just buying new parts at random?
 
so, my next question would be, how to diagnose which of those three things is the problem without just buying new parts at random?
Easy jumper across the ignition switch. If it starts and runs that way it is the switch. If that doesn't work jumper across the resister and if it runs that is the problem. If that doesn't work run a wire from the resister to the coil and well that is the last part in the circuit
 
Easy jumper across the ignition switch. If it starts and runs that way it is the switch. If that doesn't work jumper across the resister and if it runs that is the problem. If that doesn't work run a wire from the resister to the coil and well that is the last part in the circuit
I took the dist. off again cleaned points and made sure everything was working there as far as doing continuity testing. Put it back on,still no fire. So I put a jumper wire across the two leads coming from the back of the key switch (assuming that’s what you meant) and still nothing. Put a jumper across the two top posts on the resister, still nothing . Put a jumper across the grounded side of battery to coil, still nothing. There are three posts on the resister and I tried jumping the wires from top right to bottom and top left to bottom ( don’t know if that was a no no but I did it anyway) and still get nothing. Accidentally pulled a wire off the ignition switch guess I’ll buy a new switch after all.

any other thoughts on what I’m missing?
 
I took the dist. off again cleaned points and made sure everything was working there as far as doing continuity testing. Put it back on,still no fire. So I put a jumper wire across the two leads coming from the back of the key switch (assuming that’s what you meant) and still nothing. Put a jumper across the two top posts on the resister, still nothing . Put a jumper across the grounded side of battery to coil, still nothing. There are three posts on the resister and I tried jumping the wires from top right to bottom and top left to bottom ( don’t know if that was a no no but I did it anyway) and still get nothing. Accidentally pulled a wire off the ignition switch guess I’ll buy a new switch after all.

any other thoughts on what I’m missing?
Just to clear things up, when I first jumped it and it started I had the jumper from the coil to the negative battery terminal, not the positive terminal which is the ground.
 
When hot wiring you need to run a wire from the non ground side to the top of the coil.
Correct , that’s what I did the first time and it started , but then it wouldn’t work the next time I tried it.🤔
 
I know you are trying to diagnose the thing without throwing a bunch of parts at it. Good job. But at this point, I might be thinking about a new coil. Points and condenser are cheaper, you could try those first, but new condensers out of the box are iffy.
Have you looked real good to make sure the little coil spring on the coil is making good contact to the top of the distributor?
 
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If that's not a typo, jumping from the positive side of the battery actually did nothing for you accept make a spark, assuming your 6 volt 8N is still positive ground. To bypass the ignition switch and ballast resister you need to jump from negative battery post to the top of the coil. However because that temporarily solved the problem, I would be looking at loose, or corroded connections anywhere in the circuit. Ignition switch, ballast resister top of the coil and under it and like Old said, points contacts. Either fouled or not making with enough tension.
You may be able to read battery voltage through a corroded or loose connection but it won't pass the current needed for the coil.
I may have stated it wrong , I did jump it from the negative post which is the Hot side not the grounded positive post.
 
I know you are trying to diagnose the thing without throwing a bunch of parts at it. Good job. But at this point, I might be thinking about a new coil. Points and condenser are cheaper, you could try those first, but new condensers out of the box are iffy.
Have you looked real good to make sure the little coil spring on the coil is making good contact to the top of the distributor?
I've had to stretch my spring several times.
 
Hi I just went thru the same thing on my ford 9N front distributer, I cleaned everything in the fuel system including carb and drained and replaced gas, cleaned all electrical connections from batt to coil. replaced ballast cause I had one laying around. charged battery 10 hours. still no start just a one put sometimes. I had two coils so I ohmed both out both tested good. I was about to give up and start throwing parts at it but I got a note from Jmor saying not to throw parts at something you don't understand, so I changed the coil with an old one I had in the shed and BAM started on the first revolution runs better than it ever has I don't even have to use choke it just starts right up. That my happy ending to a weeks worth of work and worry.
 
Hi I just went thru the same thing on my ford 9N front distributer, I cleaned everything in the fuel system including carb and drained and replaced gas, cleaned all electrical connections from batt to coil. replaced ballast cause I had one laying around. charged battery 10 hours. still no start just a one put sometimes. I had two coils so I ohmed both out both tested good. I was about to give up and start throwing parts at it but I got a note from Jmor saying not to throw parts at something you don't understand, so I changed the coil with an old one I had in the shed and BAM started on the first revolution runs better than it ever has I don't even have to use choke it just starts right up. That my happy ending to a weeks worth of work and worry.
Thanks for sharing rock54. We don't know if the O.P. got his tractor to run or not.
 

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