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How to test an Ignition Coil on an ATC 250R

stanoo1

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How to test an Ignition Coil on an ATC 250R
« on: October 18, 2016, 09:40:24 AM »
How to test an Ignition Coil on an ATC 250R

Is there an exact procedure for checking a coil for proper operation. I have a spare ignition coil in a box of sparew parts that came with my 250R. I want to test it and see if it is worth saving. So can someone explain how to test an ignition coil for an ATC 250R.

Many Thanks!

malph

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Re: How to test an Ignition Coil on an ATC 250R
« Reply #1 on: October 19, 2016, 01:32:59 PM »
How to test an Ignition Coil on an ATC 250R

First of all, I don't know the specs for the 250R's ignition coil, but I do know how to conduct a general test that will most often rule out obvious shorts or open circuits.

The ignition coil has two independent circuits inside. It is basically a transformer that takes a small input voltage and transforms the small input pulse into a very large output pulse that is fed to the spark plug wire. If you have determined that your plug wire is good, you should test the ignition coil. Plug wires fail and they should be tested for continuity and physical damage.

On the input side, you should connect an ohmeter to the two small terminals/wires. This is the primary side of the ignition coil. There should be continuity between these two wires. A lack of continuity would indicate an open primary coil which renders it defective and in need of replacement.

If the primary coils tests good for continuity (I'm not sure of the exact ohm reading), then you test for shorts between the primary and secondary.

So going from either of the primary wires to the output socket where the plug wire goes, you should see an open circuit. The secondary coil, or high voltage side, is completely isolated from the primary side. If there is any continuity to the output port from the primary side then the coil is short circuited and defective.

The second connection on the secondary side of the coil is ground where it is bolted to the frame. If you have continuity from either primary wire to ground, you have a short circuited ignition coil and it is defective. 

If anyone has an official procedure on how to test an ignition coil on an ATC 250R, this would be a great place to post it.