testing an external coil

i have a 79 motorn medalist moped,, (6v),, and suspect the coil may be bad. I cant find a cycle shop that says they can test it.

Should i get continuity between the grounding bar that is molded into the coil and the spark plug cap?

This coil has a grounding/mounting bar modled into the coil housing. All the lighting/horn grounds fasten to the ground bar.

I also get continuity between the grounding bar on the coil and the metal stab that accepts the ingition wire from the condensor.

I'm not sure,, but i expected to only read continuty between the metal stab for the ingition wire, and the spark plug cap.

Here is a link to a few pictures of what my coil looks like,,


any help???

Re: testing an external coil

I do some work on lawn mowers .I take coils for the tractors in to a snall engine shop and they check them. Just a suggestion Dan

Re: testing an external coil

Wayne Broderick /

Get it all hooked up and put your tongue on it, with your free hand on the negative ground. That should let you know if it's allowing current through-- you can go from there

great tip dwayne

good tip!

Re: testing an external coil

Ron Brown /


From the plug wire to ground, you should read several K-ohms, maybe 5 - 15 K-ohms. From the points connection to ground you should read between 0.5 and 1.5 ohms.

To test the coil, connect a spark plug from the plug wire to coil ground, connect an ignition condensor (any will do for this test) between the points terminal and coil ground. Connect the negative of a 6V battery to coil ground and touch the points terminal momentarily with the positive lead. This should give you a spark at the plug.


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