ORIGINAL: crashlander

The YS 120SC is a powerful engine and assuming you are not flying a lead sled, (that is no over 5kg in weight) should be more than adequate.
Select a proppeller that will give you approximately 9000 RPM no more and you should be OK.
Your fuel should not contain less than 20% nitro content with 20% oil. Do not use a fuel with castor oil, it sometimes will varnish, gel and plug the small ports in the engine causing starting to be extremely difficult.