yes...if you have one good coil that works on either cylinder and one bad coil that works on neither, then that external coil is bad,..IF...the wire connections, grounding points for the coil ground wire, spark plug lead to the spark plug etc. are good...disclaimer, I have never personally fooled with this type ignition set up and what insight I have has been gleaned from other Forum members...my understanding is that each point set serves as the ground for the other point set so that is why cleanliness and grounding points for the components under the flywheel is critical ; clean grounds are essential for this system..before you condemn that coil I suggest you do the following..pull the boot off the spark plug lead < yes it will just pull off >..you'll find the wire coil that the spark plug end snaps into..pull that out of the plug wire < has a spike that pierces the wire > now cut 1/4" to 1/2" off the lead and reattach the wire coil, lube the boot with some rubbing alcohol and shove the plug coil back into the boot, check for spark..yes or no to spark now?...
