do i have this right? you had a 24p on a 150, and now a 21p on a 200?
uhh... 24p high 5 on a 150 WILL make less rpm than a 21p high 5 on a 200...
if you want to stay with the high 5, first try put the 24p that you have on the 200.
HOWEVER, the high 5 is the wrong prop IMHO for a bass boat...