black varnish lookin material on piston

[nw10er]

Hey people, can anyone tell me what this is on the piston? lookin down the glow plug hole the piston is shiny black, the engine seeems to run ok ( sure fire .32),should i tear it down and clean it or if its not broke dont fix it?
thanks

 

[beason]

its just burnt fuel and oil, you may be running a bit rich. it shouldnt hurt anything but if its bothering you you can remove it with a little 3 in 1 oil and the soft black brissle atatchment on a dremle tool.

 

[jetmechG550]

It's normal, you'll see discoloration on the piston face.

 

[nw10er]

Thanks,some one said i might have over heated ,i have got it up in the high 200s, 305 once,but that was awhile a go.Well maybe if the weather gets real bad and i have some down time, i will clean it up. thanks again

 

[jetmechG550]

How long did it run at those temps? Is your head discolored? Do you still have good compression? While running at those temps isn't good, if you caught it right away and corrected the problem you may be ok.