Reply To: 1948 Evinrude LightFour

[Mumbles]

A readily available  NGK AB6 gapped at .025″ will make a good replacement for the discontinued Champion 5M-J.  One nice thing about NGK plugs is they have a screw on terminal for Rajahs while Champions don’t.

These plugs have 18mm threads instead of  14mm as found on the four cylinder Evinrude Zephyrs which thrive on shorty plugs to prevent arcing under the front cover. The Light Fours have a bit more room under the cover so a regular length plug should work OK even with exposed Rajah.   The ignition systems in these motors are sensitive so the points must be clean and polished  and gapped precisely to .020″ for them to work properly.  The original condensers are rated at 0.20 uF and the motor requires 3/4 pint of oil per gallon of gas.

 

https://www.sparkplug-crossreference.com/convert/CHAMP_PN/D9