I have a 25pd , bought it used and the guy said he put a 32hp prop on it. On a 14x48 boat by my self top speed is around 23mph. what advantages if any am i getting from that prop? Should i be getting more top speed? Should i put the 25/27 hp prop back on it? RPM in water is around 3980 to 4000.

Try running both props in the same area under the same conditions. You will never know until you try it. Good luck and post the difference's between the two.