I started up my new Evolution .61 on 5% nitro and ran it for a few minutes. The engine idles well but stumbles a bit toward full throttle. The engine manual recommends 10-15% nitro and adjusting the "Setright bar" for leaner mixture when rapid acceleration stumbles. Would the nitro content throw off the acceleration? Also, does it matter how much oil content is in the fuel? My LHS carries 15% nitro with 3 different oil percentages.