# 1949 Farmall Cub No Spark



## horse2985

I have a 1949 Farmall Cub, that has sat around without starting for over a year. It started and ran fine back then. I had installed new plugs, cap, rotor, wires. I tried to start it and it seems not to be getting any spark. I placed a spark plug tester on the ends of all the wires and there is definately no spark. I was also told that in this model the battery wires actually go opposite, black wire on positive and red wire on negative. I did replace the plugs thinking they may be bad sitting around for over a year but still nothing. Cap internals look good as does rotor. Is there any testing I can do at the distributor to make sure it's o.k.? Any help would be appreciated.


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## Country Boy

Is this a battery coil ignition or a magneto ignition?

Almost sounds like your points could be corroded. If you take the distributor cap and rotor off, there is a plastic cover you can remove to access the points (they sit behind the rotor). Take a points file or some emery cloth and clean up the contacts on the points and see if that helps. If they were open when it was stored, they can corrode and not make contact any more. If its any more than that, I'll need to know if you have a magneto or battery coil ignition.

I'm pretty sure that is a positive ground electrical system. My Farmall H has the same setup. The black (or sometimes red) wire from the tractor frame goes to the positive terminal on the battery, and the red wire coming from the starter switch goes to the negative terminal. Many things were positive ground back in the day from cars and trucks to tractors. Everything these days is negative ground.


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## horse2985

You were right. The points were a little corroded. Although the points never saw the light of day when the tractor was stored and by my eye looked beautiful. A little emery cloth did the trick. That opened up a new can of worms with the carburetor though, which took me two days of cleaning and taking apart the carb to fix. I still am not sure about the negative or positive ground though. It's running great as a negative ground right now, but how do I know it's right? Is there anything on the tractor that would let me distinguish it?


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## Country Boy

If everything is working as a negative ground (battery charges, charge gauge works, engine starts, etc) then I would assume that you have the system correct. I don't know what year they switched over to a negative ground. My 1946 Farmall H is positive ground, and my 1956 350 Utility is negative ground. Sometime in that decade they made the switch.


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## horse2985

If I had it connected incorrectly would the battery drain while sitting? Also, how can I tell what type or what model tractor I have?


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## Country Boy

If the battery was connected backwards, I don't think it would drain while sitting. Most likely the starter would spin backwards if at all, and the generator wouldn't charge. As for the model tractor, there should be a small silver or silver/black plate riveted to the tractor that has all the serial and model numbers on it.


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## Bythepond

A 1949 Cub would have been wired as positive ground from the factory. However, some of them get switched around by accident. Having it hooked up as negative ground will not drain the battery of itself. However, if the generator was not polarized after the switch, it won't charge the battery. To polarize the generator, hold one end of a jumper wire on the "Batt" terminal of the cutout or regulator, and briefly touch the other end to the "Gen" terminal. You should see a small spark, that will confirm that the generator has been polarized.


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## Rastus

Where does the juice come from the battery or generator on a yellow cub? Im not getting any fire at all to the coil.


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## Rastus

Rastus
Registered User
Feedback Score: 0 reviews

Join Date: Mar 2013
Posts: 1
Where does the juice come from the battery or generator on a yellow cub? Im not getting any fire at all to the coil.


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## Bythepond

The juice comes from both the battery and the generator. When starting, the juice comes from the battery. When running, the electricity from the generator powers the ignition system. Check the post on the coil to which the wire from the harness connects with the ignition switch on, but the engine not running. If there is no power to the coil, work your way back through the wiring until you find power. The section of the harness after that point is where the problem is.


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## spook291

Rastus said:


> Rastus
> Registered User
> Feedback Score: 0 reviews
> 
> Join Date: Mar 2013
> Posts: 1
> Where does the juice come from the battery or generator on a yellow cub? Im not getting any fire at all to the coil.


Many Cubs are yellow .. from the original lo-boy painted in Dept of Highways Fed Yellow to the Yaller and White Cubs. What year is your Cub? Most likely yours is a battery ignition/distributor system with either a 2 pole pule ignition switch or maybe is even newer and has a key switch. Either way on a battery ignition setup the "juice" comes from the battery - either 6 volt or 12 volt depending on your system. The generator is the device that charges the battery. Pretty much what Michael said.

You need to check/read the GSS-1012 Electrical Equipment Service Manual. Follow the wiring diagrams and check all of your connections, grounds (clean bright metal). Also, the coil is the piece that provides the output or spark to the plugs. You may have a fried coil, it may be breaking down or it may simply be a bad connection. Could be a number of things. Rule out the obvious first.


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## spook291

horse2985 said:


> I have a 1949 Farmall Cub, that has sat around without starting for over a year. It started and ran fine back then. I had installed new plugs, cap, rotor, wires. I tried to start it and it seems not to be getting any spark. I placed a spark plug tester on the ends of all the wires and there is definately no spark. I was also told that in this model the battery wires actually go opposite, black wire on positive and red wire on negative. I did replace the plugs thinking they may be bad sitting around for over a year but still nothing. Cap internals look good as does rotor. Is there any testing I can do at the distributor to make sure it's o.k.? Any help would be appreciated.


The one thing that surprises me and has for a long time is that no one reads the Owner's Manuals. If you were to spend a little time reading the Owner's Manual paying attention to the Maintenance Section which includes the trouble shooting pages, it would be easier. One needs to be familiar with one's Cub if one is to maintain it properly. It is a steep learning curve at times but well worth all the effort expended.

McCormick Farmall Cub Operator's Manual 5-1-49 would be a good place to start.

Also pay attention to the terminals .... on a positive ground system it just means that the positive terminal of the battery goes to ground instead of the negative. DO NOT reverse the red and black wires... that would be dangerous. Red on say a charger is positive - connect it to the positive side of the battery and black to the negative. Polarity on the Cub means nothing to the battery but polarity means everything to the charger and the battery. Cross polarity and it will damage the battery and could cause personal injury as well.

A '49 with a magneto would be positive ground from the factory. If you have indeed changed this to a negative ground then the ammeter would have to be rewired, you would have to polarize the generator and may have to change a couple other connections. Check out the GSS-1012 Electrical Equipment Service Manual, spend some time reading it and familiarizing the manual with your Cub.


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