Spark Plug maintenance Home › Forums › Maintenance of Grummans › Engine › Spark Plug maintenance This topic has 0 replies, 1 voice, and was last updated 8 years ago by Jeff Johnson. Viewing 0 reply threads Author Posts July 9, 2016 at 13:40 #5765 Jeff JohnsonKeymaster Spark Plug Cleaning and Resistance from Tempest This topic was modified 8 years ago by Jeff Johnson. Author Posts Viewing 0 reply threads You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In