scotclayshooter
Addicted to ArboristSite
Very rich oil mixes 20:1 often result in lower carbon build up on the piston. There are several documented experiments on this topic. If there is enough oil to keep surfaces wetted and quenched with oil the oil tends to clean rather than deposit and bake on. Just like a well oil frying pan resists things sticking to it.
On a well adjusted saw the worst carbon buildup I have seen is running at 50:1 with factory reccomended mix. Ironically 32:1 left the piston crown significantly cleaner.
I would take it as fact if TW states it. Its 99.9% correct.
I now run 40:1.
I bet most of the carbon build up comes from the petrol not the oil.