I just though I’d post the photo for anyone’s comment as this is my first experience with these plugs in this engine for this many hours.  Some deposits on the leading - should I maybe consider a step toward a higher heat range?

 

Happy Holidays!

 

In olden times we could do a clean cut, read the plugs and re-jet up or down depending. But then motor fuel had lots of lead in it and would give you a color. A clean cut was from at temperature an a full throttle load, ignition off and clutch in. So you were looking at the color of an operational plug.

 

Today we have no lead, and no colors to look at. So nobody looks at plugs anymore. If you want to check for too high a heat range, check for cement boil around the center electrode, and or flecks of porcelain missing.

 

The light color with a plume of black is typical but usually the leading plug will just look dirty. Even the end of the shell will be black. These plugs are not the coldest plugs you can get. So long as the cement is staying out of sight, these are fine. You use a higher heat range if you get fouling below full throttle. You cannot hurt an engine with too low a heat range. You can destroy it with too high a heat range. I use the coldest heat range made by NGK and they don't foul. R6725-11.5 $25.00 each.

 

Lynn E. Hanover