internatial cub tractor

Do you perhaps have a magneto?

Perhaps someone swapped a magneto onto an a cub that had previously used battery ignition , and you are wireing the magnetor 'kill' line up to the coil, thus killing the maggy

Post pics.. there is usefull info missing that is needed to diagnose this problem..

Soundguy

First. Plug wire away from the spark plug.. this makes sense.. it means you have fouled plugs most likely.

Now.. your tractor can't have both a battery ignition system, AND a magneto, unless it is a shelled out magneto with a coil manually butchered and wired in using the magneto points.. etc.

So which is it? standard battery ignition? Or magneto? Or a hybred magneto that has been shelled out to allow for a shadetree battery ignition system??

the more info you provide.. the better the answers will be.
Also.. there isn't any charge for more words in your post.. please be very clear and descriptive.

Soundguy

And your spark plug fireing issue, as said, is most likely fouled plugs.

Make sure you have a coil that matches youe battery polarity and voltage, and make sure you use metal core wires,.. not carbon core.. they cut your high voltage down, and can sometimes cause the fireing problem you are seeing.

gap your points like the battery ignition settings, if there is a difference between that and the magneto settings..

Soundguy