What prop??? Help

[RAP727]

I have a 2011 Bayliner 185 F18 flight series 4.3 Mercruiser when I got the boat it did not have the original prop own it I was supposed to have got the original prop later but it never worked out the boat is running 25 miles an hour at about 5000 RPMs I know I need to change the prop maybe the size of pitch but I do not know what to go to any help would be appreciated

 

[Maverick7]

What’s on there now(pitch/make/blades)? I have a similar boat. When I bought it, it had a 3 blade 17p prop on it. It sucked, for some reason it took forever to plan out and I could only do about 30 before hitting the limiter. Switched to a 19p 3 blade, and that worked quite a bit better. Planned out faster, and I could do about 38-40. A week later, I found a stump with the prop. Went to buy a replacement and the guy convinced me to purchase a 19p 4-blade. Iv used that ever sense, and it’s been great. Planes out fast, corners awesome, and I can do about 40ish at 4500rpm.

 

[QBhoy]

I think either your tacho isn’t right or your speedo pitot is restricted or similar. If you actually only doing that speed and actually those rpm…you have a prop far too wee.