9n/8n electronic ignition timing

I've installed a new alternator and new Pertronix ignition kit (1247xt part number) on a tractor that was already on a 12V system. I removed some bad wiring and confirmed the new wiring was correct, installed a new resistor block, ballast resistor and ammeter and the tractor ran fine (after a jump due to a weak battery... ). I made about 6 passes through the field bush-hogging to test yesterday, then parked it after about 30 minutes of it running. The thing ran like a top. This morning I go out and try to start it again and nothing. A few putts but nothing more. I've tried to check to see if maybe the timing is off but can't find timing guides for the Pertronix electronic ignitions. I tested for spark, getting a good strong spark on the plugs (nice and blue). Fuel flow is good to the carb (and I smelled gas after about the 5th time turning it over). I'm guessing it flooded due to the timing being off at this point as everything needed for combustion seems to be happening. I attempted to time it by using the test meter method and look for an open circuit at 1/4" past the bolt hole like the manual says for the original distributor but I'm not getting a continuity beep or reading from the red and black wires on the ignition on full rotations. Any help at this point is appreciated as this is the first time I've had a Ford tractor to work on. Thanks again.

hi mike, welcome to YT.

u list both 9N and 8N in your subject. there are differences in the wiring for each, it's important to know which one yours is.

By the kit # you posted, it's a "front mount" distributor.

If it ran yesterday, the timing isn't the issue it won't run today (unless the camshaft gear(s) stripped).

If it has good spark (as you say) and smells of gas, it's likely you flooded it & the sparkplugs are wet with gas.

Carburetor may have "run over" overnite, and the air horn vent MAY be clogged so gas couldn't leak out. (It's never a bad idea to shut the gas off when the tractor's parked.)

You might loosen the clamp and slip the air cleaner hose/pipe off of the carb and see if there' gas pooled in there.

If the plugs are fouled, they MAY air dry with time, or will need to be burned clean with a torch or replaced.

Mike-
I can only suggest you contact Pertronix about your EI - I don't muck with them myself. 9N or 8N, wiring matters no matter which one even though if front-mount distributor is used. You have done most of the basic tests -fuel flow and spark. Replacing parts without first determining they are defective is not the usual procedure though. You say you "... installed a new resistor block, ballast resistor and ammeter...". By resistor block, do you mean the entire ballast resistor unit or is there an external ceramic 1-OHM resistor in-line? You need the OEM Ballast Resistor in all front mount 12V switch overs, and only use the ceramic external resistor with a 6V coil. Is your coil 6V or 12V? Once again, forget about wire colors -they mean nothing and don't conduct electrons. All new wiring harnesses are not created equal. Do you still have a cutout (9N/2N) or a voltage regulator (8N) in the circuit? If so, you are wired wrong. Is alternator 1-wire or 3-wire? The EI simply eliminates having to muck with points. So, how did you 'attempt to time' as in your last statement? Get the essential manuals for starters. Seek "WIRING PICTOGRAMS BY JMOR" for another essential document to have handy. Then, get your battery tested and replaced if needed.

Tim *PloughNman* Daley(MI)

So I listed 9n/8n as the tractor is a bit of a mutt. The rear end is a 9n from what I can tell (left brake is outside of the clutch) and everything forward of the dash is an 8n, judging from the serial number. After doing some more digging and looking into it, I figured out I now have a carburetor issue... Seems like fuel flow is either limited or stuck wide open. I got it running after shutting the fuel line off and attempting to start. It fired and then I turned fuel on and it ran for about 10 minutes. As soon as I engaged the PTO to lift the bushhog it petered off and cut out. My dad who's a mechanic said that shutting the fuel line off may have caused a vacuum and unstuck a float or needle to allow it to start but it's not working well enough to run under load. I've ordered a new carburetor as this appears to be the original Marvel, and I noticed the rubber hose for the intake had bits missing... Instead of screwing with clogged jets I'm just going to replace it. Thanks for the responses. I'll update once the new carb goes on.

From what I've read since posting, the ballast resistor (not the resistor block) is still used to protect the 12V coil from over voltage from the alternator when the alternator is charging. This is not needed in coils that have an internal resistor but I'm not sure if the coil in the kit I ordered has that or not.

No automotive coil has an ?internal resistor?. Internal coil resistance is determined by wire gauge and the number of turns. Higher resistance is provided by smaller gauge wire with greater turns. If the coil is marked or sold with a notice ?requires an external resistor? that simply means it has a low internal resistance and will be damaged by excessive voltage. It does not mean the coil has an internal resistor.


You either have a 12v coil or you don't. If it's a 12v coil, you only need the oem ballast resistor. See tip # 30. If you add the additional resistor, you will get a weak spark. It will be hard to start. I suggest that you find out if you have a 12v coil . If you do, remove the additional resistor.

" and I noticed the rubber hose for the intake had bits missing.." What rubber hose would that be?

" I tested for spark, getting a good strong spark on the plugs (nice and blue)."

Color is meaningless. It's the distance it jumps that counts. Does the spark jump 1/4" in open air?


" I've ordered a new carburetor as this appears to be the original Marvel, " That could prove to be a costly mistake. This board as well as a few other boards are full of posts regarding 'junk in a box' M/S clone carbs. Hopefully, you will have good luck. But my suggestion is that you have the oem carb rebuilt.
75 Tips

Thanks for the info. I'll try and find the part number for the coil and verify. If it is 12V I'll remove that additional resistor. I've also got to look into adding an "idiot light" for the alternator. It's a 1 wire but even up into full RPMs it isn't charging. I've seen a lot of folks having to do that online with 1-wire alternators (at least cheaper ones...).

The rubber hose I mentioned is to couple from the air intake tube to the intake side of the carburetor. There's a short, about 5-6" piece of rubber hose to connect the metal intake tube that goes over the exhaust manifold. It appears to be dry-rotted and some small chunks are missing so I'd be willing to bet they've found their way into the carb...

I don't have a spark plug tester that will allow me to test the 1/4" gap. I may invest in one if I keep having to tinker on this thing.

I'd not read anything about the aftermarket carbs, that's unfortunate. Hopefully YT will take it back if it's faulty... but I'm hoping for a break of good luck with this thing for once and get it back mowing. I have about 5 acres to mow and right now there's sections of it that I'd have to tie balloons to my kids to keep track of 'em if they wandered into it.

Thanks for all the info. I grew up working on Super A's, 140s and IH 574s with my dad, so the older Fords are new to me. Lots to learn!

(quoted from post at 15:04:16 08/27/18) No automotive coil has an ?internal resistor?. Internal coil resistance is determined by wire gauge and the number of turns. Higher resistance is provided by smaller gauge wire with greater turns. If the coil is marked or sold with a notice ?requires an external resistor? that simply means it has a low internal resistance and will be damaged by excessive voltage. It does not mean the coil has an internal resistor.


You either have a 12v coil or you don't. If it's a 12v coil, you only need the oem ballast resistor. See tip # 30. If you add the additional resistor, you will get a weak spark. It will be hard to start. I suggest that you find out if you have a 12v coil . If you do, remove the additional resistor.

" and I noticed the rubber hose for the intake had bits missing.." What rubber hose would that be?

" I tested for spark, getting a good strong spark on the plugs (nice and blue)."

Color is meaningless. It's the distance it jumps that counts. Does the spark jump 1/4" in open air?


" I've ordered a new carburetor as this appears to be the original Marvel, " That could prove to be a costly mistake. This board as well as a few other boards are full of posts regarding 'junk in a box' M/S clone carbs. Hopefully, you will have good luck. But my suggestion is that you have the oem carb rebuilt.
75 Tips

Click to expand...

Bruce, I owe you a case of beer my friend. Bypassing the additional (ceramic) resistor resolved the issue. Not sure why that isn't better documented. The wiring guides I found across the internet with 12V conversions included that resistor, even on wiring diagrams for kits with 12V coils... I made a jumper and bypassed it and she fired up and ran better than ever. I can really tell a difference in this tractor with the electronic ignition. I'm in the process of documenting (via Youtube video) the process I went through for the front mount distributor upgrade, as I didn't find any videos for a front mount. I'm guessing the front mount design was an early one, and Ford improved access to it with the side mount design. Thanks again!

You're welcome. Glad to help.

Ford first came out with the front
distributor in 1932 on the new V-8 and kept
it in production until 1949. So the
technology was used on the 9N in 1939.

At least Henry didn't put dual points in
the tractor distributor like he did on the
car!

A little late to the game good you got it going... How did you come up the the need for an additional resistor... It looks like it came with a round can coil did they advise an additional resistor...

To time'er... You will need good advanced skills to do it if it runs good leave it alone...

(quoted from post at 21:38:08 08/28/18)
A little late to the game good you got it going... How did you come up the the need for an additional resistor... It looks like it came with a round can coil did they advise an additional resistor...

To time'er... You will need good advanced skills to do it if it runs good leave it alone...

Click to expand...

The additional resistor was on the tractor when I bought it, with the 12V conversion already done. Not sure if the coil I took off was 12V or not as there are no markings. Honestly couldn't find any wiring diagrams that did not have that extra resistor. I spent an hour on Google looking through loads of wiring diagrams and pictures and could not find one that they removed it... I'm making a Youtube video about my experience to hopefully save some other poor sap from the same frustration!