Originally posted by afm
It's carbon deposits from the oil than burns off the fuel during combustion. Depends on fuel you are using, but mainly because of over rich mixture. Now, all fuels leave that layer over a long period of running, that's why I clean them after every 3 races, but if you're getting those layers after one run, your engine is tuned to rich.
AFM
That was very helpful afm! thank you!
Also i would like to ask a question concerning the black deposits!
Would the same thing apply if you treat your engine with after run oil after the weekend?