Just another thougth.

Make sure also that your carb is fully seated and that the o-ring that seals the carb is in good condition.

The English manual calls for 0-15% nitro on all the engines...while italian version calls for 0-10% nitro.

As a general rule for all the engines...I wouldn't take it, I would try first and see what works best.

The more nitro in the fuel doesn't mean always more power, if the engine can't handle the nitro content so good. There are engines at their best at 5% nitro.

Saludos