Danni,
why not to report your experiences on the tread on fuels and additives?
A remark, lecithin contais phosphor, and could lead to gumming, did you experience it?


Sloper,
I guess the better trotthling when adding mineral in place of castor is deriving from the percentages you use. When idling, the higher viscosity of castor has its effect. Why not to reduce the castor percentage in place of substituting it?
Castor has exclusive hydroxyl bonds that neither olive nor mineral have. This means that is far more superior to both for extreme stresses, both mechanical than termal.
I suggest to go simply reducing its percentage progressively down till to one fifth of the oil content, that is 80 olive, 20 castor, not less. No mineral.
Pls keep informed if you try, and report the resulting choose on fuels etc.