39 Farmall H No Spark

wrg4257

New User
I have worked my wood lot since the late 1980's with this 39 Formal H. It's a work horse and I rely on it. I have just enough mechanical skills to keep it running.
Every 12 to 14 months my H stops running. I have gotten used to replacing the points, condenser, rotor, etc. and the coil. Then it runs again until it stops again. Before I do this this year I dug into the problem to find out why.
With the ignition switch on I can get spark on the distributor side of the coil. I can get my test light to flash when I open and close the points by hand, at the coil and at the side of the distributor. The light is sensitive enough to begin to glow just as the points begin to open and shines brightly when the points are completely open.
However, when I turn the engine over to open and close the points the test lamp does not flash.
I believe this has something to do with my problem.
Any ideas/comments will be appreciated.
Thanks, WRG
 
Sounds like points have a film or corrosion so they do not make good contact when closed, but doing it by hand adds more pressure and makes then activate.

Rub a folded dollar bill through the closed points and see if that helps. If not, I use a piece of emery cloth with grit sides folded together, then spray a puff of electro-motive cleaner on the cloth side and rub that through points. If they still do not work it's time for new set. Allow them to set for a minute or two if using the cleaner so cleaner can evaporate and dry.

Use good quality NAPA/Echlin or Standard brand points, not the cheap ones that come in a tune up kit.
 
Buy a good old cheap points file cost about a buck. As points get older they tend to get a burnt spots on them and then they do not work like they should. Cleaning them will make them last a whole lot longer.
 
If the test light stays on while you are cranking, the points are not making contact. Could be they just need cleaning or adjusting. Watch them carefully when you are spinning it over, should see them moving. Also check the distributor shaft bushing for wear. The shaft needs to have very little play, otherwise the point gap will not stay set.

If the test light is not coming on while you are cranking, possibly the ignition switch is bad or a loose connection.
 
Shes never gonna run until the points fully open and fully close good with no resistance (due to carbon or pitting or burning or oxide or not fully closed) when closed. With ignition on and a test light on the coils LV primary output to distributor if shes cranked over the light should flash ON (points open) and OFF (points closed). So often bad burned or pitted or coated points is the cause of no spark or else a bad condenser.

If you work through my Ignition Troubleshooting Procedure below it can find the cause of no fire

John T
John Ts Ignition test
 
I used very fine sandpaper, but it makes no difference because the way they control and trouble light (off to full on) I figured they are working OK.
Thanks for taking the time to answer.
 
I bought a file years ago when I used to tune my motorcycle.
Points are OK.
Thanks fort answering.
 
I hope the bar is working properly because I use it to open the points and set the gap.
Thanks for your response.
 
I used your list last year when I had this problem. I learned a lot and got my H running simply by putting in new condenser, points, and coil.
I ended up doing the same thing this time, but instead of a cheap coil made in China, I bought one from YT.
H started right away!
May I assume that the China coils go bad in about 12 months whether the H is being used or not. This is the 3rd coil in 4 years. First 2 came from China.
I sure would like to know if it is the coil or something in 39 H is causing the coil to go bad.
Thanks for your help.
Love you forum guys and appreciate you time!
Bill G
 

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