Spark Plug Chart

  • FBO Ignition no longer offers spark plug readings over the phone or email, please use this information as a reference.

    Additional tuning information available in our Tuning to Win book. Click Here

Oil Fouled

Oil Fouled

Carbon Fouled

Too Cold

Too Cold

Cold or Rich But OK

Cold or Rich But OK

Cold or Rich But OK

Good

Good

Good

Good

Real Good

The Best

Best

Best

Best

Good

Good

Good

Kinda Hot But OK

Kinda Hot But OK

Kinda Hot But OK

Kinda Hot But OK

Too Hot or Lean Pre-Ignition Range

Too Hot or Lean Pre-Ignition Range

Too Hot or Lean Pre-Ignition Range

Too Hot or Lean Pre-Ignition Range

Too Hot or Lean Pre-Ignition Range