Factory engines with delivered props gives very good performance on light to medium light applications, usually at near full wot factory stated rpm. Install the induction tach, go for a wot spin you alone with lightly loaded boat on ideal flat calm, no wind water cond. and check achieved max wot rpm, compare them to engine's factory wot parameters to check if inside safe ones.
That engine revs 5-6K rpm, check if in that range, can play with prop pitch to be at or very near 6K. One -, + prop pitch is around 150-200 rpm difference,