Originally Posted by
Roelof
There is no direct telling about light or darker colored pistons, it depends the fuel. The higher the volume of the castor oil the darker the piston will get.
That makes total sense. I was seeing a light brown piston top, then I was advised to add some castor oil to my fuel, after the first day of running with the extra castor the piston was noticeably darker. Thanks for the info!