Hola Pereira,

I know that Troy (The YS guru) has been doing some research using the fuel. I think he needs more time but probably he is going to respond to your question. I know that there were some discussions in the NSRCA opinion group.

My guess that if the fuel is Low Viscocity, it is natural to get richer and probably you need to lean the engine some.

Saludos,

Vicente Bortone