After 2 years of deep contemplation I decided to Buy a 4 stroke engine. I bought a Magnum XL .61 RFS. I need to know if I can run my Byron 15 percent nitromethane, 20 percent synthetic/castor blend fuel on it.

The document that came with this engine says that for break in I should use fuel with no more than 10 percnt nitro, and no less than 20 pcnt libricant. BUt, after break in I should use fuel w/no more than 15 prcnt nitro and no less than 16 prcnt castor blend.

P.S. What is a 4 stroke .61 equal to in 2 stroke terms?
Thnx in advance.