Prop question

[Pipymagic]

Hi, I am new to boating & new to this site. I have a1984 Wellcraft 18' with a 140 mercruiser 3.0 and I nerd a new prop. The prop that is on it is a 14 x 19 & plastic. At wot I'm at about 4000 rpm. Hole shot ok top speed is about 28 mph. I would love any & all suggestions. I'm looking for all purpose type but would like to hear all suggestions. Thank you.

 

[steelespike]

Re: Prop question

Typically a setup like yours would be close to over revving and might over rev with a 19" pitch. And with a composite prop even more so.
Is your speed by gps? If all the numbers prove accurate your motor would be suspect.
You need to confirm the tach is accurate, perhaps borrow a shop tach.
Is the bottom clean and smooth?
Does the throttle open all the way?
is the timing set right and advancing as it should?
Is there a hydrofoil on the out drive?
Do you trim up for best speed and does the boat respond to up trim?