What is up with my hp?

[bolderdan]

I have a merc 650 outboard with distributor cd ignition. The full throttle rpm is 4800 - 5300. I want to pull a tube or skier but feel the boat doesn't have enough power. I think it may have to do with the prop. It is a 48-61814A1 11P. Do I need a larger pitch. Without a skier on a calm day, my boats top speed is 25ish mph. The boat is a 1975 15 ft sea sprite. Please help me figure this out?

 

[steelespike]

Re: What is up with my hp?

If you read the stickies at the top of the page you will understand prop selection better.
Apparently there are 3 versions of the 650. 1 of them the 11" pitch is roughly in the middle of the chart.The other 2 close to the smallest pitch. Also there is a 2:00 gear ratio version.
If you check the prop selections here at iboats you will see what I mean
Typically a 650 on a 15ft boat should easily run 30-40 mph. I do believe you have a motor issue.
Is the 4800-5300 the rated rpm or your actual rpm?

 

[bolderdan]

Re: What is up with my hp?

The 4800 - 5300 is the rated rpm. The prop I have now is a little beat up. It does have a few nicks and dings. The motor sounds great and has been taken care of.

 

[Mi duckdown]

Re: What is up with my hp?

Bolder. you need to know the actual rpm before going further. And you know it is 25 mph,How? gps,speedo,??