I have checked the butterflies and they now go to hrizontal, but the 18 ft 86 bayliner capri only does about 31 mph and the motor wont reach 200 rpms? its revs there quick enough , but just wont pull past there. previously the motor was only having the butterflies open about 1/4 so it revved slower but same results ,maybe 30mph at 1600 rpm...now the throttle opens better it should pull more revs...???