# no spark getting to plugs



## Mark Taylo

My '41' Ford 9N is getting erratic spark to no spark at plug . Checked connections around ignition switch and sprayed WD 40 . Noticed resistor coil on inside dash glowing hot. Is this a ground issue?


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## harry16

Hello Mark, welcome to the tractor forum. 

Has this tractor been converted to 12V? 

The glowing resistor coil indicates that you may have a short circuit somewhere beyond the resistor.


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## Mark Taylo

Yes, been converted to 12 v. Took off distributor cap to check points. Point gap practically closed , so replaced and gapped to specs. Will put it back together tomorrow and see what results! Funny though that it ran well shortly before it failed. Stay tuned!


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## RufusMax

Mark, when I had a similar issue it turned out to be my breaker plate. Insulated rivet inside lost its insulation. Easy to check with a meter. Good luck.


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## Mark Taylo

Ok see if point replacement works getting spark to plugs.


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## Mark Taylo

Still no spark., replaced "can"type coil with same results. Tightened up lose ground resistor plate under side of dash with no results. only thing left is distributor cap and rotor.


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## RufusMax

OK Mark, I don't want to get repetitive, but I'm not sure by your description if you looked at the breaker plate. This is the plate the points are mounted on, and while the points are replaced routinely, the breaker plate is not. Easy way to test is with the distributor out, put a meter across the points, and rotate the distributor by hand. It should open and close as it turns. If it conducts regardless of turns, the breaker plate might be it. I apologize if you've already covered this, just wanted to be sure.

The great thing about the 8N, you can replace the electrical system from one end to the other and you're not out that much money ;-)


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## FredM

these ignition systems are as a simple as can be, the breaker plate has to go to earth to make the circuit and the only insulation in the breaker set is where the flat spring connects to the wire tail from the coil on the fixed contact plate.
were the contact faces badly pitted when you first checked these?, have you replaced the condenser?, usually this is done when fitting new contacts, a failed condenser will give you your symptoms.
on the inside of the distributor cap on the center pole, is there a carbon brush there in good condition?, this may be fixed or spring loaded, the rotor will either have a flat spring to contact the fixed carbon brush in the center pole or the rotor may have a flat on top for the spring loaded brush to make the circuit, this has to be in good condition to make a good circuit for the spark to follow.
you can check out the coil by removing the HT lead from the center pole in the cap, set the contacts to open by rolling the engine a little by hand, turn on the ignition to the run position and with a flat blade screw driver bridge across the contacts while holding the HT lead close to a good earth and observe the spark, if you can get a good spark with about 1/4" gap, you will be good to go.
the next check would be all of the HT leads, if these are old, the leads could have a high resistance and this will upset the spark output to the plugs, these can be checked later with an ohm meter.
with the resister glowing, I wonder if this was replaced for a 12 volt one, or if this is still the original 6 volt resistor?, you know you don't really need these in the circuit, their only purpose was to prolong the contact faces life, you could bridge across the poles on either side to see if this improved the spark too, if it does, you could join the two wires either side of the resistor and bypass this altogether, this is your call.
lets hear how you go.


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## Mark Taylo

Decided to go with electronic conversion kit for sake of ease. I know it's kind of a cop out but fighting through a Dearborn bucket to get at the distributor is a bitch! The breaker plate looks fine though haven't taken it yet again to test it Note: have taken it out three times with bleeding wrist to prove it! The tractor is dead in the field so removing bucket not an option. This is a 12 volt negative ground with automotive conversion with delco alternator, except whoever converted it patched in exterior coil wire into original coil to distributor! Don't know how this was done but has been working fine until recently. Maybe some short in the old coil to distributor, not sure. Already replaced exterior coil, points , condenser, with no results. Thanks for all advise!


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## FredM

whoever converted it patched in exterior coil wire into original coil to distributor!

I can't follow that Mark, there should be an ignition wire from ign. switch to the positive side of the coil and a wire from the negative side of the coil to the distributor.


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## RufusMax

OK Mark, let us know how it goes. I'd be interested to know which electronic kit you bought and how much. Good luck!


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## willys55

same here, what kit did you buy


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## Mark Taylo

For the record, mine is a 41 9N. 


FredM said:


> whoever converted it patched in exterior coil wire into original coil to distributor!
> 
> I can't follow that Mark, there should be an ignition wire from ign. switch to the positive side of the coil and a wire from the negative side of the coil to the distributor.


Yes!


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## Mark Taylo

I bought the conversion kit from yesterday's tractors. A bit pricey but I've paid more for scheduled maintenance on my truck. Frankly tired of trying to figure out what previous owner( now deceased) did but need to get this thing up and running. Thanks again for all responses and advice!


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## Mark Taylo

Change of plans. Pulled out distributor and bench tested with exterior coil from a 12 volt battery. Test spark plug fired . Know now distributor functions.. Next put everything back in tractor and tested neg. post on coil with ignition wire.no power from this directionWhen ignition turned on resistor glows red! Any ideas? Do I have a faulty coil resistor, bad ground, or ignition switch?


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## Mark Taylo

Found faulty/burned resistor cause of problem.


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## harry16

Hey Mark, thanks for the follow-up report. This may help others in the future.


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