Jubilee/NAA wont start

I have spent the better part of the last month trying to get my Jubilee to start. I have tried to read every available forum to see if anyone else has the same problem, but I am running out of ideas for what the issue might be... any assistance would be greatly appreciated!!

The tractor last ran a few months ago, and died in the middle of running after about 30 mins. Since then I was able to get it to crank enough to get it into the garage, but it didn't run well. I thought it might be a wire short, so I started there. The tractor has been converted to a 12V, negative to ground.

I have rebuilt the wiring harness, using all new GPT hookup wire per the original suggested coloring and gauges. The ends are all crimped and heat-shrinked. I replaced it one wire at a time, so I feel fairly confident there.

I seem to be getting a good spark - it is bright blue and will jump 1/4". The coil is a new NAPA IC-14. I have put on 3 sets of points, all gapped to 0.025". I have put on 3 condensers too. All parts from Steiner or Tractor Supply... not doing any cheap shopping on Amazon/eBay.

I have bypassed the ignition key, replaced the distributor cap, wires and button. All new spark plugs, 437, with 0.025" gap. The distributor has been timed using several different methods, and it is in the same position as when it last ran. The battery is being kept trickle charged, and is 12.5-13V. Battery cables are brand new, soldered and heat shrinked. Good ground connection.

All that to say, I don't know what else to do from an electrical perspective...


From a fuel perspective, I have put on a new fuel tank, new sediment bowl, new fuel line. The tank is full of new non-ethanol gas. The carb has been rebuilt twice, and cleaned thoroughly. When I open up the fuel line and have the bottom drain plug open, I get a steady steam of fuel going to the carb. The float is set to 1/4", and the bowl seems to fill up and then cut off fuel flow properly.

When I turn over the engine with a spark plug removed, I get a strong whiff of gas.

All that to say, I don't know what to do from a fuel perspective....


The air intake and oil bath is as clean as I can get it. So I don't think that is the problem. Besides, I can try to crank it with the air hose disconnected and that doesn't change anything.


Best I have been able to do was get it to run for ~5 seconds and then it dies. This was with an improper coil (1.5 ohm across the primary instead of 4 ohm), and it ran decent and then dies quickly. I hooked up some lights to the spark plugs, and they indicate good spark to start and then it dies... almost like it loses spark.

The spark plugs are getting fouled up with me cranking on them so much, so I try to pull them out often to clean them.


Any ideas on what rabbit trail to chase next?? My gut is telling me I am overlooking the obvious and that it is spark related, but I am at a loss for ideas. I'm thinking about putting in electronic ignition just to rule out the points/condenser and give it a little better spark. Any suggestions would be appreciated!!

Welcome to the forum. What you incountered is real common and even the best tinkerers are
trown by it the first time around. Condensers are junk now days but one brand still works for
me. Call your auto parts house and ask for Standard brand's Blue Streak condenser. If
they are unable to find your tractor in their catalog ask if they have or can get Standard
Blue Streak for 1957 to 1967 Ford cars. Try and match mounting configuration if they have
pictures. If you can't find correct part, steal one off any older 12 volt point ignition
car,truck or tractor. If it doesn't mount like it should,remove existing condenser then mount
this one on coil. It must have a perfect ground so if you can't do that with a screw just use
a jumper from tractor to condenser body. The tractor will run like that but the least amount
of moisture (think fog) will make it useless. You would do us a great service by reporting
whether this was the problem or not. I assure you that we will help you get it up and going
so hang in there and ask all the questions you like.

And of course simpler would be go to tractor salvage or find any 600 or 800 to rob a condenser.

FACT: 99.98% of all non-starting issues are due to incorrect wiring regardless if OEM 6V/POS GRN or a 12V NEG/GRN switch out job. The smell of gas and presence of fouled plugs means it isn't fuel so leave carb alone and move on to the wiring. If carb throat to air cleaner isn't full of gas, leave air cleaner alone as well -it's not your root cause problem. You can buy all the best gold plated wire connectors in the world but if it ain't WIRED right, you will have issues. First, take the battery to a local shop and have them test it on their special machine for specific gravity. It must sustain a full load under load for proper ignition and charging. You can't just apply a trickle charge to your battery and think that'll work nor think that because you just bought it last year it is good to go. Some batteries are plain junk out the door. The bargain house brands are most likely to fail in early life. Get a good brand. Keep it on a float charger when not in use -DELTRAN makes a good one. While battery is out, disconnect lights for now and go thru the entire wiring system using a correct, reliable sketch like JMOR's WIRING PICTOGRAMS. 6V or 12V, he has all the right ones. Use your VOM set to continuity, not a test light, and do not use wire color codes as a guide. Not likely to be OEM correct especially if new, plus, colors do not conduct electrons. The correct battery cables are a must -6V needs thicker ones than the 12V ones like on your car or truck. A 12V job means you swap out the GEN and the VR for the ALT to do it right. ALT or GEN, either one, requires a belt tensioning device. No belt tension means you will never charge the system -ever. The starter motor is a 3-Wire unit with a Solenoid. Wiring harness has to be altered for 12V. They make new ones that will fit for both 6 and 12. The rest is basically the same --key switch, AMMETER, start pushbutton, and distributor. Having the distributor timed correctly (with a timing light)is all important as well but get wiring right first. If you use your 6V coil, you will need an external, 1-OHM resistor in the coil circuit but may opt to just spring for a new 12V coil and eschew the extra resistor. There are no oil or temp gauges that operate on the electrical. The AMMETER is a passive device that works on induction. Lights were never factory items -always dealer optional equipment - and many are wired wrong, especially with 12V and a cause of non-starting. Lastly, do not start replacing parts with new until tested to determine if defective. A lot of folks have made comments in the past few years of defective condensors and/or Voltage Regulators without a true test. Granted, no doubt there are a lot of Cheena made junkers out there now, but Ive never had a bad VR or condensor. It takes very expensive, professional, and sophisticated equipment to test a condensor. Bad wiring is the usual culprit in your situation. Once corrected, you can work on distributor and timing. Lights can be added back in once all else is fixed. FWIW & FYI, the OEM 6V Electrical diagram is shown.

FORD TRACTOR OEM 6V/POS GRN WIRING DIAGRAM; NAA/600/800/900:

NAA/600/800/900 12V SWITCH OUT:
NOTE: NEUTRAL SAFETY START PUSHBUTTON SHOWN DISCONNECTED NOT RECOMMENDED! 6-V COIL NEEDS AN EXTERNAL 1-OHM RESISTOR.


NAA & 600 TIMING SET @ 8 DEG BTDC w/TIMG LIGHT THRU INSPECTION PORT:


NAA OWNER/OPERTORS MANUAL:


Tim Daley(MI)

da.bees: Thank you very much for the warm welcome and encourgement! I will pick up a Blue Streak Condenser tomorrow and see if that provides the fix. I will definitely reply back with my findings.

Tim: Thank you for the feedback on checking the wiring. I will chase that rabbit trail next. You are certainly right, electrical gremlins can be some of the worst to try and track down and diagnose.

Thank you again for everyone's time to try and help me troubleshoot!

bngroves, You said you suspected a short right at the beginning. Have you checked the terminal on the side of the distributor where the primary wire from the coil connects? That insulator can go bad and the terminal can short to ground.

Alright, so time for an update!

I got the recommended Blue Streak condenser last night and installed it. Unfortunately it did not do anything to help. Same issues.

BUT, in messing around with it, I accidentally discovered something.... the square indent knob on the distributor shaft was loose! It would swivel back and forth maybe 20 degrees.

As you can see, the shaft does not have much play in it, but the square knob and that opens and closes the points does have a lot of play. When I took the distributor apart, there was a piece of metal about 1/2" long that was rattling around in there (I can't figure out where it came from). That piece of metal would jam the internals whenever the distributor would get up to speed (due to the flywheel action of the distributor weights). I think that piece of metal might have broken off inside when the tractor died a month or two ago.

Tim, I think this might mean that I am in the 0.02% where the non-starting is not due to incorrect wiring...

A new distributor is on order, so I will check back in once I get that installed.

Here is some proof:

https://youtube.com/watch?v=jQbDz95Qylk

[note: Post edited to get the link to show up properly. To the mod's, I apologize if this is not kosher to post a link to a video. If you want me to delete this post, I am happy to... just trying to add value to the community knowledge/experience bank]

This post was edited by bngroves on 07/29/2021 at 06:24 am.

I installed the new distributor last night, and she runs like a champ now! Thank you to everyone for your support/encouragement... glad to have finally found the problem!!

Thank you for the update. Glad you got him running well. Don't be a stranger on here.