Home › Forum › Ask A Member › 50s Johnson sparkplug? › Re: 50s Johnson sparkplug?
August 26, 2017 at 1:54 am
#63797
I did notice the H10 & H9 plugs have (t) note that says they are 7/16" reach threads. That might make them stick thru the head too far? You would not want the edge of the threads in the combustion chamber. I agree they are up the heat range a bit too far! Might be good for trolling only?
Easy enough to make "C" plugs into "J" plugs. Just file the ground strap back until it only covers half of the center electrode. You then have the old "J" style plug.
Dan in TN