3.0 mercury won’t rev past 3600

[Had112]

I recently bought a 1989 sea ray with a 3.0L mercury. It had a 17p prop on it and it would run 30mph at 3800. I then put a 19p prop on it and it will now only run 3600rpm at 30mph. Any idea why it won’t rev past 3600? It starts hard everytime. Once you get on plain it revs up slow and then stops at 3600. If you give it more throttle it makes the engine sound like it’s choking

 

[alldodge]

You increased the prop pitch and the boat slowed down, yes that's how it works

With your WOT rpm being at 3800, you should lower pitch not increase it. Your motor should be able to reach max WOT RPM, which in your case should be 4600

Being that low to start with I would suggest a compression test and tune up if pressures record in the 140 or higher range