ORIGINAL: SManMTB
If you run to rich there will be NO deposits on the piston or anywhere else in the combustion chamber.
The ideal setting should yield a slightly brown/golden surface that can be wiped away with paper.
What does the filament in the plug look like?
If it's shiny and straight you are running on the rich side.
If it is slightly silver-dull you have tuned the engine for maximum power.
If it's pushed-in/distorted you are lean.
This assumes you put a new plug in before this run. Otherwise it will be hard to diagnose.
Hi the plug was sooty too black and oily...i will try & tune the engine again tomorrow, i did take the head off and clean the top of the piston & change the plug we'll see what it does tomorrow, my final may have been something to do with it maybe i ran in 3 finals (1 hour non-stop) could have been the problem, maybe running rich for proloned peroids burns the oil that is hanging around...i'n not an expert but more suggestions would be welcome
Thanks guys