spark plug condition?
 

1992 500sl. I have been adjusting the fuekl mixture and the rough idle has disappeared.
Can I find out if it's too lean by the color of the spark plu electrode after a few miles? white, brown, black, ash color being what I'm looking for I guess.

The DYI information is pretty complex and I adjusted the mixture to the place wher the engine was running smoothest, I'm concerned about running too lean and causing damage to the engine. opinions please.

Overly lean condition will produce pinging, usually at low RPM under moderate to heavy load. Try getting into highest gear on the highway around 60 mph and applying heavy throttle, though not enough throttle to cause a downshift. If the mixture is lean, you will likely hear pinging.

great observation, thanks:)

love the car:)

really, too, if it is too lean it wont idle correctly or run smoothly.

lean running should make your plugs white. black is too rich. light brown is the correct color.

in the old days of lead gas a light gray coating inside the tail pipe was indication of correct mixture too. but now there is only black which in the lead days indicated too rich.

tom w

I thought that a light brown was good.

thanks.