location of carbon deposit-what it says?

[Ed Cheung]

Hello Folks,
When I took off the cylinder heads, I notices that the carbon deposit is very thin on the priston, I can pretty much rub it off and see the numbers the piston head. but on the higher up the cylinder things seems to get worse, the cylinder head inside the Combustion is like 2-3 mm thick.
What does this tells me, bad mixture, air and fuel is not mix properly, weak sparks, bad timing?? Anyone?

Thanks in advance.

Edward

[TEMPL4R]

You will get a deposit on the bore, above the point where the top ring gets to, Ed.

Too much black deposit on the heads is usually carbon/soot from unburnt fuel. If it is oil residue, it is usually tacky.

Chris

[Ed Cheung]

Thanks Chris, So the deposit on the heads means I am throwing out unburnt fuel => weak sparks or over fueling issue I am having. As the plugs wires are replaced 12 months ago, I think it should last for another year, spark plugs got new set already, and make sure no leaks in the exhaust system, besides those 3 points, anything that need attention?

thanks
Edward