How do you test the coil on your Ford 8N tractor?

Answer 1

To test most any coil, you'll need to "pulse" it with a battery. (Why not use the battery right there?) Disconnect the "hot" wire from the coil. It's the one that goes to the distributor (where the breaker points are). Now take the high voltage wire out of the distributor center, leaving the other end in the coil. Place the end of that open high voltage wire, the one you took out of the distributor, on a metal part. The trick is not to actually make metal-to-metal contact, but to set up a "spark gap" between the end of that high voltage wire and the metal. Use whatever grounded metal is handy. The valve cover, the exhaust manifold, whatever. You don't have to set up a specific sized gap. Anything from a quarter inch to an inch is okay. You just need to be able to see the gap.

Now get a wire and connect it to the positive terminal of the battery. Then take the other end and briefly touch the side of the coil you removed the wire from. (The other end of the coil is the side of it that is grounded, so it's connected to the negative terminal of the battery through ground.) By "pulsing" the positive side of the coil with the "hot" wire you just hooked up to the battery, you should see a spark across the "gap" you set up. That's a go-no go test most wannabe mechanics use (and some real mechanics, too!).

Note! The spark is "real" here. Insure there isn't a lot of fuel vapor "floating around" when you're conducting your test.