Look at this plug...

[P Dubya]

One side of the plug looks pretty decent... Other side looks rich. Any ideas on how this happens/what causes it?

 

[kiwigtx]

One side of the plug looks pretty decent... Other side looks rich. Any ideas on how this happens/what causes it?

View attachment 1904616

Try installing it on the opposite side of the engine - it should clean up.

 

[Geoff 2]

The centre electrode is getting fuel wash on the grd strap side.