Ounces No, Pounds Yes. If his fuji is more than 2pounds heavier than the recommended engine then he will probally need and extra half of a pound just to balance it out. It will fly but once again will he really enjoy it? Start off the right way with a GS aerobat and you will be very pleased. And know with the new string of light powerfull and descently priced 50cc class engine you can't go wrong.