Jd lawn mower was only firing on 1 side coil and i changed coil so why is it still not firing
You only have one magneto on the flywheel, this is how any flywheel is designed because both cylinders can't fire at the same time, so why have two magnetos to fire one coil? Anyways, the magnetos on flywheels from my experience hardly if EVER go bad, and coils today have so many capacitors and resistors and diodes inside that even the slightest amount of heat soak from a poorly maintained engine can fry the circuitry and fault a coil in a flash. If you replaced te coil and it won't work, try to swap the coils around and see if the one you know works won't fire on that non-working cylinder, that way you can be sure the new coil is not defective, which I've seen many times as well. When it's running, do you pull the plug off the dead cylinder and see if it fires, then repeat the procedure on the live cylinder with the dead coil installed on the plug? Will it fire at all? Try to disconnect the kill wire from each coil, then start the engine and see if both cylinders fire now. I have seen some engines, as an example some briggs vanguard v-twins that have a diode right in the middle of the kill switch wire. I don't know why it's there, probably to deal with spikes in current or something, I'm not that great with electrical I just know how a simple ignition system works and I know if one coil fires that plug, the other one should too. As I said, things from china areive defective all the time, it wouldn't surprise me if that coil is defective or if it runs with the kill wire disconnected from the coils, then there may be a diode blown in the line or you have a chafed area of insulation that's grounding to the book somehow. Pull the kill wire and fire it up, then swap coils, you'll be able to tell what's wrong once you rule out one or the other, it's just a simple process of elimination for a simple problem once it's explained to you. I'm sure you'll figure it out and be back running in no time I you attempt my suggestions!
on Mar 02, 2015