ok, im trying to determine the state of my engine from my plugs. they have been in for about 6k miles and i decided to pop them out and take a look. as far as i can tell the enine is healthy and running strong, however i just wanted to make sure and ask about a few observations i had.

-the plugs are a dark cocoa color. the leadings are a shade darker than the trailings. are the trailing suposed to be lighter?
-the tan buildup, is easily scratched off with a screwdriver to uncover the bare metal electrode. (im prety sure this is good)
-this is the strange one. botht leading and trailing, but leading moreso, have what looks like a stripe of oily gunk acrost 2 of the oposite pie-wedge electrodes. it didnt feel oily, but it was much darker and softer than the rest of the buildup. what is this stripe about and shouild i be concerned?
-the center electrodes were all worn down to hemishperes but still at the same height as when they were new. this means i need new plugs right?
-if i do need new plugs, isnt 6k a little early and should i stick with the stock ngks?

some extra info: im running strait premix and i did the water trick with 3 gallons of distilled about 1000 miles ago.

 

medium tan and black is what you're looking for. This indicates proper running conditions. Leadings are exposed more to the combustion gases than trailings, due to the diameter of their holes, so they usually show more than the trailings.

Sounds fine to me.

 

http://www.theultralightplace.com/sparkplugs.htm

 

No digital camera?


-Ted