Plug reading

[jaybee]

I found a pretty good and detailed illustration about reading plugs.

[Crosley.In.AZ]

Nice illustration.  Similar to one I found a few yrs ago  , this has much better explanations...  thanks

[kb426]

That's good. It only applies to gas engines, though. I bought a Champion spark plug reader decades ago. It was really poor. The light bulb wasn't centered to hit the plug. The magnification power wasn't enough to be useful. A good magnifying glass would be very useful.