Reply To: Johnson P-35 coil

[Nicholas Keller]

Some spark testers have a .030 or better gap. These coils often fail spark testers because the ignition systems are often designed for a .020 gap on the spark plugs. That extra .010 is asking a lot out of the coils in question especially if the magnets in the flywheel have lost a little flux (magnetic field has weakened) over time. Find the right old timer and they have the right old school stuff and they can re-magnetize the magnet cores in your flywheel. However in most cases that isn’t really needed and the bench tested or spark tested coils with plugs properly gapped fire just fine.