1987 20 ft Aquasport Osprey speed question

[Jonwilliam]

Hi all
I have a question about speed of my boat. What should be the top speed with a 1989 Evinrude 90 2 stroker?
Engine only has about 150 hours at the most and runs like a top. I can tell what the prop specs are as they are not
stamped in the prop. I usually can go about 27 mph at 4200 rpm per my gps but that's the max i can get. But the specs say 4500 to 5500 WOT
I just learned about trimming but always kept the motor all the way down to the transom. Somebody today to trim the engine
away from the transom and I will gain rpm and speed. Just wondering what i should be shooting for.  Also I have bottom paint
and its been in the water now for 2 months. Can't see any growth from the side. Should i jump in and check the bottom?
How long does bottom paint last? Also any owners manuals around.
Thanks for all the help in advance! Jon

[Capt. Bob]

First off:
Pull the prop. You may find the diameter/pitch stamped under the nut/washer assembly.

Second:
4200 is too low at WOT. Of course a 20' isn't going to tear up the seas with a 90 hp motor but low to mid 30s may be doable. Learning to properly trim your motor is an art not a science and what kind of load do you usually carry?

First get back with the prop size.

Good luck.

[Jonwilliam]

Ok will do and thank you