If you are cutting with it bouncing on the limiter or 4 stroking in the cut it will make the plug look that way too. Start with a new plug get a long log about bar length across. Make about 20 cuts heavily loaded but not bogging or slipping the clutch. Kill the saw without letting it idle atall. Then look at the plug all tge way at the bottom of the porcelain down inside the plug where ut meets the steel. You should be able to look up a chart on how to read the plug its hard to describe without pics.. Nice fleet of saws
@August76 do you think any of them are redundant being so close in ccs and hp?