Igntion Coils Causing Stress

[bob]

I have a John Deere LX176(Kawaski FC420V) with no spark with kill wire diconnected. I measured primary and secondary coil and they were not shorted or open so I was not sure coil was defective. So I decided to remove the the coil from a John Deere 160 ( Kawaski Fb460v) I had. The coil looks the same and fit with bolts and I new this coil was good since I had tested it with coil tester before removing. Put it in JD LX176 and it did not work either which was confusing to me. Then I put it back in JD160 and now I have is no spark there. So i have went from one dead coil to destroying another. What did i do. I thought I would see some type of spark by swithing them but did not count on destroying it. Are the coils that sensitive that a different magnet can destroy one. Should I have just ordered a new coil in the first place when I had no spark and not tried another which I now is not the same part but it is from the same manufacturer. Thanks for help

Blair

[hanz63]

I guess that I would compare the part numbers for starters. Did both have an external ignitor and were they both the same?

[bgsengine]

might be a bad igniter? no idea if this particular model has igniters, but if they do, might be just bad igniter and coils are fine?

[KE4AVB]

When switch the coils did you connect the kill / ignitor wire on the FC420? And then when switching the coil back to the FB460 reconnect the kill/ignitor wire to the coil?

And yes both these uses an ignitor (electronic points). But to be sure what is both of the engine spec numbers?


Plus if you got a pulse or constant voltage on the kill/ignitor wire it can destroy the ignition coils and/or the ignitors.

[bob]

Sorry for delay in replying but having computer problems. No I did not re connect the kill wire back up. I thought you could test coil with kill wire disonnected and that would eliminate any problems from safety switches etc. Now I have John Deere 160 working again thanks to you but still have to figure out LX176. Is there any way to verify if igniter module is working other than ohms measurement

[KE4AVB]

Basically all you can do is to test that the igniter terminal is not grounded in the run position. Think of the coil like it is Briggs Magnetron coil. The only difference is that the trigger module is outside the coil and is replaceable.

[hanz63]

BTW should you need an ignitor, those little Rotary modules work out real well.

[bob]

Thanks Hanz. Can you be a little more specfic to what you are referring to

[KE4AVB]

Rotary 8786 Universal Igniter

[hanz63]

Actually the one I've used : https://www.rotarycorp.com/product/9334