Magneto Trouble How to Test and What is next?

B

buddylindsey

Active member
First I have no idea what I am doing, I am still learning. Reading manuals, forums, magazines, and YouTube so...

I am not getting any spark from my magneto. I replaced the points and condensor, no luck.

After that I replaced the coil tonight. It is too late to try and put it on the cub tonight so I can't test it.

Is there a way to test if it is working? It seems like if I turn the magneto it should spark, but I get nothing. I just realized I am probably turning it the wrong direction.

I tried putting a cable on the ground where the button connects and touching it to metal, and still nothing.

I am hoping tomorrow or Thursday to be able to put it back on the cub and give it a shot.

However, is there a way I can test before hand?

If I am still not getting spark, is there something else I could check?
 

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Since I realized I was probably spinning it the wrong direction I went back out and spun it the correct direction, and I got spark. WOOHOO. Now, if I can get some time tomorrow to put it on my cub it will be amazing.

I also had my finger in the wrong place and also felt the shock :D that was fun.
 
Hi,
They have said on here to not turn the magneto and make it spark without somewhere for the spark to go. It can damage the magneto to turn it and make sparks without somewhere for the spark to ground.
Put a spark plug wire in the coil post and hold the wire so the end is 1/4" away from the metal of the magneto, or a bare place on the engine block, if the magneto is on the engine.
The spark should be blue or white, and jump the 1/4" gap. A yellow spark is weak, the engine may not run, or run well with a yellow spark.
It is easier to see the spark if the magneto or tractor isn't in bright light.
There is an impulse coupling, it is called, at the magneto drive. It should be hard to turn by hand, then make a snap sound when it releases.
Below are pages from the 1947 Cub owner's manual telling about the magneto.
https://farmallcub.com/rudi_cub/www.cle ... age-30.jpg

The page below tells about flushing the impulse coupling, on the right side of the page. I would do that when the magneto is off the engine.
https://farmallcub.com/rudi_cub/www.cle ... age-31.jpg

The page below tells how to time the magneto to the engine.
https://farmallcub.com/rudi_cub/www.cle ... age-32.jpg
 
There should be timing marks on the rotor and it's drive gear. Be sure the marks are aligned.
Also, clean the old grease out of the area, and put new grease on the gears, if they haven't been greased lately.
Below is a pic of the timing marks. :)
 

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Alright the magneto is on the cub now.

I double checked the timing marks they were correct. New grease looks good.

I ran through the static timing video and my cub does the exact same thing, so my assumption is that it is timed correctly.

Cub still doesn't start, but I think I am going to ask in a different thread some different questions.

I just thought I tested the cable coming out of the top of the coil against the edge of the cub for spark, and it sparked. I did not however test that spark made it to the spark plug... sigh I guess I should double check that too.

On the bright side I am learning. I am trying to do this without asking my father-in-law for help as he could probably solve it in 5 minutes, but I want the struggle so I can learn. And struggle I am. lol.On to the next battle.
 
I unplugged every cable and replugged in. I think some might not have been seated properly.

The spark plugs are now sparking.

I also got the tractor to run for about a minute. It is a bit rough, but it ran. I think it is slightly out of time.
I need to tweak the magneto.

Also need to rebuild the carb, once those are done it should be usable.
 
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