(quoted from post at 13:46:14 08/18/23) Okay, I just ordered one. Will be here tomorrow. I have to work all day tomorrow at my teaching job so that will work out just fine. I'll try and use it Sunday after church. Will I need to attached it to each individual spark plug wire or is one enough to confirm if the coil is sending enough juice or not?
This post was edited by Chris623 on 08/18/2023 at 01:48 pm.
Thats the beauty of it. It can test the spark between the coil and distributor...and it can test the spark between the distributor and the plugs.
Start at where the coils output wire connects to the distributor input (top center of the distributor)
Disconnect that wire from the top of the distributor...plug that into your spark tester... clip your spark tester to the block somewhere... try to start the tractor. You should see sparks. at the tester, if your coil is good.
My suggestion is to start with the gap at maybe 1/8" or even smaller. If you get any spark, increase to the 1/4" and re-test.
Using a small gap gives you the best chance of seeing something, so you get a little confidence in your new handy-dandy tester.
Get your feet wet, before you go and try to get an exact measurement.
Other suggestion is, it's nice to have a partner to sit on the seat and crank the engine for you, so you can concentrate on the tester. Just remember to keep hands off while cranking...otherwise you'll get a nasty jolt.
Then...if you have a good, 1/4" spark with your tester connected at the coil output wire's input to the distributor ...plug your coil output wire back into the distributor... and then you can test the spark plug wires individually by pulling them from one plug at a time and connecting them to the tester.
If you don't have spark at the coil wire...then troubleshoot the other direction... go from where you are testing back towards the coil itself.
If your tester has a ground cable on it, you can maybe plug it into the top of the coil itself...and retest...if you get spark, you have a bad coil output wire.
If no spark there...
put down your spark tester and go back to the coil input, make sure it has voltage when you turn on the key. You can check that with a multimeter...it may not be full battery voltage during cranking, (if you try to crank) because the points create momentary short circuits to ground (by design)...so the voltage at the top of your coil may average out to something less than battery voltage during cranking. If you see a common sense DC level at the coil input... and no spark at the coil output...sanity check your grounds and such...if your sanity check pans out... then you probably have a bad coil.
If no voltage at the coil input when your key is on...trace that wire back towards the key switch with the multimeter.
So...spark tester tests from the coil output through the distributor to the plugs.
multimeter is your friend from the coil input back towards the key.
One way or another, you will isolate your problem.