Spark Plug Adapter Frequently Asked Questions

Q: Can I use a resistor sparkplug instead of a non-resistor one?
A: Yes! It takes approximately 10,000 volts to make a resistor sparkplug spark. Most all magnetos produce  over 30,000 volts, and coil ignition can go as high as 70,000 volts.

Q: Do I have to replace the adapters when I replace the plugs?
A: No! The adapters can stay in the engine. 

Q: Is the sparkplug with adapter  deeper or shallower on the cylinder?
A: The “firing location” of the sparkplug with adapter will be in the same location as original one except for the pipe thread adapters in which case, the sparkplug will be slightly shallower.

Q: What do I gap the 14 mm sparkplug to?
A: Always gap your sparkplugs to the original specification, unless you have a high energy ignition, in which case you can run a wider gap.

Q: My engine specifies a very hot sparkplug that cannot be found in 14 mm.
A: Most 14 mm plugs do not run as hot as some of the older sparkplugs do. But remember, many old engines ran on kerosene or distillate which required a very hot plug. If you are running one of these old engines on gasoline, a cooler plug should be used.

Q: My tractor starts hard so I want to use a hot sparkplug.
A: A hotter sparkplug has no effect on the starting ability of an engine. The heat range of a sparkplug is established at the “normal” operating temperature of the engine.