Reading Spark Plugs

[Cincy4Runna]

I did a few searches and came back with no info on this subject. I was curious if anyone could post a detailed tutorial on reading spark plugs (e.g. coloring and what story it can tell you about how your engine is running) Gracias.

 

[slowginjoe]

try this:

http://www.buckeye-illinois.com/sparkplugs.htm

or this:

http://www.gnttype.org/techarea/engine/plugs.html

 

[Cincy4Runna]

Awesome!, Though, i know Rotax is also a type of 2 stroke. Since they use 2 stroke oil could the readings differ from that of a car motor? (I know there's rotary car motors as well). As you can tell my knowledge on motors is kinda slim. I know the basics, and that's about all. Thx for the help !

 

[slowginjoe]

yeah, in 2 strokes the oil is mixed with the fuel so some of the conditions may not apply, like the fuel/oil mixture being incorrect. but most conditions such a lean or rich fuel/air mixture is the same. white plug = lean/running hot, dark = rich or improper combustion of fuel, etc.

i believe the second link i posted is more informative and appropriate for a 4 stroke.

 

[Cincy4Runna]

Reason i ask is because when i replaced the plugs and wires button/cap the plugs were almost all very light grey. From what i remembered white meant lean and lean meant bad. So i was just concerned. I should pull one of the plugs and take a look..