8n no spark when hot

Hello everyone. Thank you in advance for any and all help.

I have been reading around the internet and havent been able to find a problem that matches mine exactly.

Back story/ history is as follows.
Tractor is an 8n that belongs to my father. front mount dizzy and a 12 volt conversion with 3 wire alt. 2 days ago I completely rewired the tractor (12awg) on everything. I used a new ballast resistor and ignition switch as well as new plugs and wires. I am told that kid up the road replaced the dizzy a few weeks ago(not sure if just the cap or the entire assembly). After I finished the wiring, the tractor fired right up so I drove it down the driveway and back up( about 1/4mile total). I then hooked up the brush hog ....engaged the PTO..... and as I released the clutch she started to bog. I drove across the lawn in a pass that was already mowed and she was extremely boggy and ran like garbage. I came to a stop and shut er off to think for a moment. When I tried to start her back up, she wouldnt come to life. I pulled #4 plug wire and stuck a big Phillips in it and held it on a ground and to my suprise...... no spark. So I let her sit and left for the day. I had my father attempt to start it the next day and shur enough she fired to life.

Sorry for the novel but I want to provide enough information to help anyone willing to help me.

(quoted from post at 14:09:04 09/09/19) Hello everyone. Thank you in advance for any and all help.

I have been reading around the internet and havent been able to find a problem that matches mine exactly.

Back story/ history is as follows.
Tractor is an 8n that belongs to my father. front mount dizzy and a 12 volt conversion with 3 wire alt. 2 days ago I completely rewired the tractor (12awg) on everything. I used a new ballast resistor and ignition switch as well as new plugs and wires. I am told that kid up the road replaced the dizzy a few weeks ago(not sure if just the cap or the entire assembly). After I finished the wiring, the tractor fired right up so I drove it down the driveway and back up( about 1/4mile total). I then hooked up the brush hog ....engaged the PTO..... and as I released the clutch she started to bog. I drove across the lawn in a pass that was already mowed and she was extremely boggy and ran like garbage. I came to a stop and shut er off to think for a moment. When I tried to start her back up, she wouldnt come to life. I pulled #4 plug wire and stuck a big Phillips in it and held it on a ground and to my suprise...... no spark. So I let her sit and left for the day. I had my father attempt to start it the next day and shur enough she fired to life.

Sorry for the novel but I want to provide enough information to help anyone willing to help me.

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'm going for the 'homerun' here &suggest that you did not replace the ballast resistor with the proper 12250 resistor. If not, then do so or put the old ballast resistor back.

I tried the original ballast resistor before I purchased a new one. I'll check the part number of the new one and update with my findings. Thanks for the quick reply

for a quick check, jumper around the resistor. if it still doesn't start, it's time to look elsewhere.

After is lost spark I taking coil wire straight to terminal block with out any change.

Waiting for my father to check part number on resistor still.

^^^^^EDIT^^^^^

AFTER I LOST SPARK, I TRIED TAKING

You said, "After is lost spark I taking coil wire straight to terminal block with out any change." So it's a side mount 8N? You never said in the original post. That means it doesn't need a ballast resister. You are talking about a step down resister for a 6 volt coil. Try putting the old one back on. It doesn't have any moving parts, unless it goes open, it isn't worn out.

Update

The resistor used was a 8NE10306 (0.6 OHM)

(quoted from post at 17:04:03 09/09/19) Update

The resistor used was a 8NE10306 (0.6 OHM)

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re you sure it is 0.6 Ohm? I ask, because 8NE10306 are notorious for being any of a wide range of resistances. However, it sounds like you tried running without any resistor, just direct connection to power, so even if it is incorrect value, it matters not, as there is a problem elsewhere. Is it correct that without resistor, it starts, runs until warm/hot then will not run?

The .6 ohm figure came from the package . WITH resistor, it will run until hot. Once it's hot, bypassing the resistor doesn't yield a different result.

(quoted from post at 17:17:37 09/09/19) The .6 ohm figure came from the package . WITH resistor, it will run until hot. Once it's hot, bypassing the resistor doesn't yield a different result.

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he front distributor tractors had a resistor as part of the three terminal block behind dash. Is that still there and connected? Is the coil atop the distributor a 6v or 12v coil?

Only the resistor I installed is in the circuit now. And how do you tell if it's a 6 or 12v coil.

Only the resistor I installed is in the circuit now. And how do you tell if it's a 6 or 12v coil.

(quoted from post at 18:09:44 09/09/19) Only the resistor I installed is in the circuit now. And how do you tell if it's a 6 or 12v coil.

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ther than knowing waht was purchased, a person can very carefully measure the primary resistance (top stud to spring line 'pig tail' and find it to be around 1 Ohm or around 2.5 Ohms, or measure current thru primary when connected to a known voltage.

Just got back from the old mans property. The resistor reads .7 ohms and the coil reads 1.4 ohms

It's the distributor. First thing is to verify the battery is at full charge and checks good under load. Simply charging the battery does not ensure that it is good. You need to know if it is a 6V Coil or a 12V coil first. Pull the distributor off and take the coil off the unit. Then take your VOM out, set to 'OHMS' scale, and put one probe (it doesn't matter which is which, checking static and the coil is not polarized anyway) to the Pigtail contact on the bottom and the other probe to the terminal stud on top. A 6V coil will read approx 1.3 OHMS and a 12V coil about double that. Once you verify your coil is 6V or 12V you can then proceed from there. If you have a 6V coil on the front mount, you will need to add an inline, ceramic 1 OHM resistor to the circuit. If you have a 12V coil, no extra resistor is needed. You say you have the correct Ballast Resistor for the front mount. Was there something wrong with the old one? Swapping out new parts for old willy nilly without knowing first if old ones are bad is a mistake often made by newbies and some oldies as well. Aftermarket parts mean nothing- they can vary one place to another. Get the OEM MPC for the correct part numbers to identify your supplier. I use a reliable supplier like nnalert so there's no question. Next is to verify the wiring is correct -seek "WIRING PICTOGRAMS by JMOR". Why did you decide to completely rewire the tractor? Were they old and worn? Did the tractor run before you changed it? You relied on a kid who said he 'replaced the dizzy'. Mistake #2. If you or your kid doesn't know the correct way to mount the front distributor, you can easily get it 180? off location and the fist time it gets power it's burnt toast. Doing the proper tuneup/dizzy rebuild is a necessity. If you or your kid do not know the procedure, find someone who does. That means setting the points to .015" gap and setting the timing correctly. Then you test it before you mount it. So, moving on. Assuming the Ballast Resistor is correctly wired, distributor on. Measure the battery voltage static and remember or write it down. Take your VOM and set to DC Volts. Take a probe, again it doesn't matter which one, not a polarized test, and set it to the LH terminal post on Ballast Resistor looking at it from the back of dash. This is the one that feeds to the coil -that's all it does. next, turn key switch 'ON' but do not turn over the engine. Then place the other VOM probe to ground anywhere and you should be reading HALF you battery voltage reading you remembered to write down. If test passes, repeat only move the resistor terminal probe to the top of the coil post. You should have the same reading which means your ignition is getting power. If the test fails, you have something not wired correctly. Check the Ballast Resistor LH terminal to see if is the coil wire. Once coil test passes, and you still don't have spark, its safe to assume your distributor is mucked up. The points/timing/condenser/ are not set correctly or you mounted it wrong and you busted the distributor aluminum base at the offset cam unit. If the latter, your distributor is trash and needs replacing. I suggest to get an OEM unit and rebuild it rather than a buying a new aftermarket part. The tang on the distributor is offset and matched to the cam on the engine. If it isn't exactly matched and is 180? off, it won't set flush and will break the unit. Member Farmer Dan is an expert hand at rebuild the Ford distributors and has about half dozen front mounts correctly rebuilt and ready to go. His email: [email protected]

FORD FRONT MOUNT DISTRIBUTOR BUSTED CAM & WEIGHT UNIT BASE FROM INCORRECT CAM TANG SETTING:

Tim *PloughNman* Daley(MI)

JMOR or someone can most definitely correct me if I'm wrong, but I don't believe you have enough resistance in your circuit and its overheating your coil. I think you should be at about 4 amps for your coil. A 12v circuit isn't truly 12v. It's more around 14.5. Using ohms law with the information you've provided 14.5 (volts) 2.1 ( your total resistance) = 6.9 (amps). I think you may need another resistor to bring it down some.
Someone please correct me if I'm wrong. I dont claim to be a professional :shock:

(quoted from post at 11:34:17 09/10/19) JMOR or someone can most definitely correct me if I'm wrong, but I don't believe you have enough resistance in your circuit and its overheating your coil. I think you should be at about 4 amps for your coil. A 12v circuit isn't truly 12v. It's more around 14.5. Using ohms law with the information you've provided 14.5 (volts) 2.1 ( your total resistance) = 6.9 (amps). I think you may need another resistor to bring it down some.
Someone please correct me if I'm wrong. I dont claim to be a professional :shock:

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orrect. The reason I had not already chimed in is that while current needs to be reduced, I have a feeling that it will not fix his problem, unless the coil has been permanently damaged, in which case he needs new coil and reduced current.

I'm going to answer the questions that I know the answers to in bullet format for ease of understanding what I'm trying to say.

1. Coil has 1.4 ohms so I'm assuming that its 6v

2. Old resistor had a ungodly amount of resistance and the tractor wouldn't fire after the rewire so I bypassed it and it fired to life ( so I replaced it.)

3. Wiring is correct. I googled 8n 12v wiring diagram, which brought me to this website and to a comment to us one of JMOR's Pict-o-grams. It was too easy to understand

4. Rewired the tractor because it was a rat's nest of twisted/taped "connections" and someone also used wire nuts instead of butt connectors.

5. Tractor was not running before I started working on it.

6. Before last week, I lived over 1000 miles away from my father. He has 0 mechanic ability so he relied on " the kid down the road" for his tractor "repairs".

I still owe you some answers which I'll post today after I go out to where the tractor is at.

Thanks for the help so far

I forgot to mention that while I was testing the coil resistance yesterday, I noticed a nice big crack down the side of the coil.

Can I replace it with a 12v unit PN : 9N12024-12V.? There is 1 available in town at Rural King.

(quoted from post at 13:34:43 09/10/19) I forgot to mention that while I was testing the coil resistance yesterday, I noticed a nice big crack down the side of the coil.

Can I replace it with a 12v unit PN : 9N12024-12V.? There is 1 available in town at Rural King.

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es

(reply to post at 11:22:22 09/10/19)

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Installed new 12v coil today and mowed for about 45mins. Shut the tractor off and it starts right up now( repeatedly)

Fixing that problem allowed me to uncover another problem..... IT RUNS LIKE $H!T. When it was idling it sounded like a cammed HONDA (terrible). She also lacked power ( pto enabled and disabled)
I found that if I kept my hand on the choke knob and adjusted it, it would run a little less $H!tty.

I gotta ask, how does a coil get big rip/tear in it? Your wiring pictogram would be the best source to use for all electrical wiring on N's. "Ungodly amount of resistance". How much is 'ungodly' and how are you checking it? I don't think I've ever checked resistor values, no need. Don't worry about it -resistors are supposed to get hot, have a lot of resistance. Do the coil test as I said. If wiring is correct, distributor tested OK, and a good coil, all should be right with world. Using a new wiring harness is OK as long as it is wired correctly. Buying a new coil: don't rely on what the box, says check it yourself. Having the kid down the road work on it is fine as long as he knows what he is doing.

TPD

Ok so today i started by draining the fuel from the tank. I disconnected the line at the carb. Inoticed that the fuel flow was poor at times. It would drip, then lightly stream, then flow great, then repeat -- almost in a rhythmic manner. Tank looked great inside ( replaced in the past couple of years. After fuel was drained i washed and blew out the 3 screens. I refilled er and started it up with out any change. A bunch of popping and loping. I was going to try to do a cylinder cut out type test by pulling 1 plug wire at a time but when i reached for the 1st plug boot it shocked the snot out of me. Is this normal.... in not used to working on things with spark plugs.

Also I belive that the quality TIWAN coil cracked from repeated thermal expansion

(quoted from post at 21:18:52 09/11/19) Ok

when i reached for the 1st plug boot it shocked the snot out of me. Is this normal

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yes. that spark consists of a whole lot of voltage.

(quoted from post at 17:18:52 09/11/19) Ok so today i started by draining the fuel from the tank. I disconnected the line at the carb. Inoticed that the fuel flow was poor at times. It would drip, then lightly stream, then flow great, then repeat -- almost in a rhythmic manner. Tank looked great inside ( replaced in the past couple of years. .

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Sounds like your tank cap isn't breathing.

Had a similar thought during the draining process. Pulled the gas cap and no change to the flow