are you getting good air to the carb? do you have a big flamearester or the small one ? did you re set the trim ? if you have more engine and want more mph why do you want more rpm? with a bigger prop you will get more mph at a lower rpm? if it jumps out and get on plane then try a bigger prop ?them points are like i said junk and will not take hi rpms. i would tune a lot of them at the boat yard six engines a day. and they where ok for lower rpm if it a mallory it may do it if the top cam is not all whip out . but if prestolite they are no good