need help

[dahill]

i am new in boating need some help please.
i have restored a 1975 duo mystery 17 with
a 63 evinrude 75hp on it.
after 4 years of rebuilding finally took to
lake to test.
boat runs 26 mph at 2900 rpm

what kind of rpm should this motor run?

how can i get more rpm and mph?

[David Borg]

your engine should spin around 5500 rpm , you either have a very big prop or a problem with your engine

[dahill]

pull prop off. barely make out what it is.

( michagan p j 7 5 ) i think. any ideal what size this is