Without tearing apart the powerhead on my Merc is there anything I can do to tweak and modify the motor for better acceleration? For example can I upgrade the carbs, wires, plugs, etc? I don't want to fool with the prop sizes because she accelerates pretty good with at 13 and revs a little high with an 11. I am researching before buying a pair of 9 x 9 Lencos. Any ideas?