Help-question on bravo 1
 

i have a 28 scarab excel 454 with a bravo 1. I cant get my boat to run wide open without over revving. i am running a 23p mirage 3 blade and i cant imagine i have to run bigger than that. i have it a little past half throttle and i am already up to 4600 where the 330 motor should rev up to. if i give it more gas it revs up more but goes no faster. someone said to find out what gearing i have in the drive so here is what i got. For one full turn of the motor the prop spins only 2/3 the way around. that doesnt seem like alot to me. what gear ratio is that. does anyone have any ideas for what is going on. id appereciate the help