Farmall Cub

After getting it all going I am worried I mixed up the coil wires
currently I have the wire from the side of the dist, going to the neg on the coil and the wire from the battery going to the positive its all working rather well
but is this the correct wiring
thanks
Rocket Man,

It is right if you have a negative ground system. If you have pos ground you will need to reverse them. An early Cub was originally pos ground.

Wondering why is it running then
perhaps I did remember the positive ground I was just reviewing in my head and reading the old manual
or does it run with the coil either way.

thanks

It'll run either way. I think the points will last longer if it's wired correctly.

Scrivet wrote:It'll run either way.

True. The difference between coils is in the way the secondary windings are grounded. Some secondary windings are grounded to the coil case. Most are manufactured so that the secondary winding is grounded to a coil terminal according to which ever way the current is suppose to be flowing.

I think the points will last longer if it's wired correctly.

Points, condenser, and coil primary winding are part of the ignition systems primary circuit. Current, voltage and amperage, passing though the primary circuit does not change because the coil's secondary windings (grounding system) is changed around.

Cannot locate my copy quickly, but IH issued a service bulletin sometime in the 1950s for their spark-ignited trucks on the subject-- so they considered it to be a matter of importance.

Positive Grounded Battery:

- Wire from distributor to coil should be connected to the (+) Positive terminal on the coil.

- Wire from ignition switch (switched power) to coil should be attached to the (-) Negative terminal on the coil.

Edit: Found on another site.
Neg ground system,connect neg coil post to ground through the distributor. Pos ground system,pos coil terminal to ground through the distributor. Thing is that it is much easier for a spark to jump from a hot contact(center plug electrode) to a cool contact (side plug electrode). This effect is so pronounced that it is why a radio tube works as a rectifier,allowing an easy flow in one direction and very hard in the other. This same effect was used in the old Tungar bulb battery chargers. If coil polarity is reversed you need much higher voltage to jump the gap in a warm plug.

thanks all wires flipped and all good
seems I will need to rewire I swear it is all original wire,.