My 3 cents (because of inflation) is that it's a dead plug.
Bingo bigted! This plug that was new at the beginning of the year was completely deado. I did get a run out of it since the time of my previous posts. I've got about 4 of these Champion BJ8s all useless.
I robbed an RJ19LM from a 4 stroke and apart from verging on being too long to get the plug lead on works a treat. I even managed to get it to run a bit slower...or did I imagine that?
Danny