Farmall A electrical mishap

A

Ahut

New member
A friend has Farmall A cultivation is what side has on it. anyway it been sitting for 5 years, they wanna get it running and i like the challenge. so i was going to try and jump it to see what it would do. COMPLETELY ignorant of old tractors, hooked to jumper cable to my truck and charged then tried to start it. after 10 min i was then informed that this tractor runs on a 6 volt system.
My question is the starter while try to turn but will not start, what and where should i start i n diagnosing the issue. Currently i have found the fuse and it good, i did double check the spark plugs and they def need replacing. any help for an ignorant curious fellow appreciated.
 
After sitting that long, you should put a few squirts of engine oil in each spark plug hole. Besides getting some lubrication on the cylinders, it will help compression and make it turn easier. Don't expect the starter to spin the engine at 1,000 rpm. 6-volt systems (maybe I should say systems of any voltage before the 1970s) typically do not turn over very fast. Follow what tst said. If it won't start, determine which of the 3 is missing and diagnose the missing piece.
 
all this has been helpful, compression i have not check, and am honestly not sure how to check compression, to see if the engine turns i guess i can grip the fan and turn that? what is the best way to test spark? As far as fuel, i drained the tank, the sight glass and cleaned that, and drained the rest of the fuel lines then added fuel as well as a little sea foam and Lucas fuel additive.
 
Jordan Goodwin said:
Not only are they originally six volt, but also POSITIVE GROUND if someone hasn’t converted it.

Is the engine free? Not locked up?
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best is can tell mine is negative ground, the ground cable goes the chassis and the positive goes start to the Starter.
 
Ahut said:
My question is the starter while try to turn but will not start, what and where should i start i n diagnosing the issue. Currently i have found the fuse and it good, i did double check the spark plugs and they def need replacing. any help for an ignorant curious fellow appreciated.
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You can remove the starter and connect it directly to a battery with jumper cables to see if it will run. Also use a large screwdriver or similar tool on the ring gear teeth to see if the engine C/S will move. If it will move add some lubricant to the cylinders as Jim Becker posted and if the fan belt is tight enough you might turn the engine by that method if the plugs are out. After you have the starter working and the engine turning with the starter you will need a compression test tool to determine what the compression is on each cylinder. Loaner tools are sometime available at an auto parts store. When you have these two checks done and working satisfactory you can determine the spark test. JMHO Stan
 
staninlowerAL said:
You can remove the starter and connect it directly to a battery with jumper cables to see if it will run. Also use a large screwdriver or similar tool on the ring gear teeth to see if the engine C/S will move. If it will move add some lubricant to the cylinders as Jim Becker posted and if the fan belt is tight enough you might turn the engine by that method if the plugs are out. After you have the starter working and the engine turning with the starter you will need a compression test tool to determine what the compression is on each cylinder. Loaner tools are sometime available at an auto parts store. When you have these two checks done and working satisfactory you can determine the spark test. JMHO Stan
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got it. all that make sense, i did go back and i may actually have a positive ground, so there a good way to confirm that? or just try rotating the terminals
 
Ahut said:
got it. all that make sense, i did go back and i may actually have a positive ground, so there a good way to confirm that? or just try rotating the terminals
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Not sure I understand the statement. Positive ground simply refers to which terminal/post of the battery is connected to ground. BTW, if this Farmall A ignition system is powered by a magneto DO NOT connect any electrical power from any source to it!! Permanent damage is likely to occur. Good Luck!! Stan
 
staninlowerAL said:
Not sure I understand the statement. Positive ground simply refers to which terminal/post of the battery is connected to ground. BTW, if this Farmall A ignition system is powered by a magneto DO NOT connect any electrical power from any source to it!! Permanent damage is likely to occur. Good Luck!! Stan
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Stan your last post confirms my fear, i am afraid i fried something when i connected my truck to it through jumper cables. not knowing about 6 volt system. when took the ignition
Cover off teh part wiht the red arrow to it wsa correded and the coil inside look black.
2025-08-01_13h33_25.png
 
Also i really appreciate the attitude of help and information , i really truly am thankful for all your patience and information
 
Ahut said:
Also i really appreciate the attitude of help and information , i really truly am thankful for all your patience and information
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If you only connected the jumper to the tractor battery it should not have caused any damage. The part with the red arrow appears to be a condenser. If this represents a tuneup kit for a Farmall A the black square cover with a single outlet is the magneto coil cover. There is a wire from the coil that's under that cover that goes to the breaker points, the 2 piece contact set. Not unusual for these parts to get corroded over time and non use. Again, the magneto makes the electricity to run the engine and is totally independent and separate from the battery and the rest of the tractor's electrical system. This is called inductive current. If you want more info send me a DM. Stan
 
The magneto makes its own spark, no other wiring is required to make it work
do you have a blue spark ??
do you have fuel getting to the carb ??
does the engine have at least 85 lbs of compression or more needed to make it run ???
these are the 3 things you must have
jumping the tractor would not affect any of this
 
Ok so an update i put new spark plugs clean all contact point in the ingition module or whatever that called. Honestly not sure what blue spark is. Currently when I try and start the tractor the starter will engage but do not think I am getting spark at the ignition.
 
Ahut said:
Ok so an update i put new spark plugs clean all contact point in the ingition module or whatever that called. Honestly not sure what blue spark is. Currently when I try and start the tractor the starter will engage but do not think I am getting spark at the ignition.
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You can test the coil output by removing the coil wire from the center post of the distributor cap and hold it about a quarter inch from a good clean metal ground somewhere on the engine. (The picture is a J4 Cub mag but shows what it should look like.) With the switch on and the starter turning the engine you should have a crisp blue spark jumping the gap between the end of the wire and the grounding point. If you have spark the coil is sending fire to the dist cap. if no spark something is wrong with the coil. If you have spark , repeat this test at the plugs. If no spark at the plugs then there's a problem under the dist cap. If you have spark at the plugs and compression is good and fuel is available as tst described the engine should attempt to start. If it does not attempt to start with spark etc. the engine and/or mag may be out of time. Did you remove the rotor when you cleaned the interior of the dist? Did the rotor have "teeth" around the outside edge? Correct timing of the rotor requires matching the timing marks on the rotor and pinion gear that drives it. Timing the engine requires matching the firing of #1 position of the magneto to the #1 spark plug. That's a totally different step. Good Luck Stan
 

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since you write that you are ignorant of old tractors. fist thing is download the operators or owners manual and read the whole thing to get an understanding of the machine you have.
 
Hello all been a minute since I started this thread, life happening hahaha.
Update is this I confirmed the engine spin very freely, I confirmed it a positive to ground and have wired correctly. I did replace the spark plugs after finding 3 of the 4 burnt. Also took the ignition apart and cleaned best I knew. Found a lot of corrosion, check for blue spark which I am not getting. This lead me to try ohming the ignition coil which if I did correctly I was getting no ohms. All of this make me wonder if I should change the ingition pack as a whole?
 
Ahut said:
Hello all been a minute since I started this thread, life happening hahaha.
Update is this I confirmed the engine spin very freely, I confirmed it a positive to ground and have wired correctly. I did replace the spark plugs after finding 3 of the 4 burnt. Also took the ignition apart and cleaned best I knew. Found a lot of corrosion, check for blue spark which I am not getting. This lead me to try ohming the ignition coil which if I did correctly I was getting no ohms. All of this make me wonder if I should change the ingition pack as a whole?
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If you do not get any spark like I posted earlier, likely the coil is bad. There is no fixing it except to replace it. To repeat, the magneto makes its own power to run the engine so don't try to bypass that unless you are going to rewire it to run on an external coil which is a whole nuther subject!!!! Stan
 
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