Suggestions for mercruiser 2.5l

[timm4433]

I am running a mercruiser 2.5l in a 1999 bayliner capri. I currently have a 3 blade 21 pitch prop that is looking pretty rough, I would like to replace it. The 21 pitch prop works great when it is just used for cruising however it is slow out of the hole. Unbearable for a skier and can't break a plane when it is loaded to max.

I am looking for a prop that will work for water sports more than anything. As it is right now with just the wife and I, WOT is at 41000 max with the trim up slighlty and the boat is going faster than i really need.

When the boat is loaded to capacity(or slightly over) it struggles, can't break a plane and WOT is 2900 rpm. I am looking for something that can help get to plane quicker, pull a skier and I don't really care about tops speed. Any suggestions would be great.

Thanks

 

[Scott Danforth]

I had to have 2 props for my 3.0, one for cruising (19 pitch), and one for watersports (15 pitch). I didnt have enough motor to use one prop for everything, and you are running half a liter less displacement

at 4100 RPM lighlty loaded, you are not at WOT of 4500. at 2900 RPM fully loaded, you are significantly lugging your motor (read that as really bad for the motor)

my suggestion is to drop down in pitch, and when lightly loaded, back off on the throttle. you may want to try a 17 pitch.

 

[steelespike]

Do you know the gear ratio?Do you know your gps speed at 4100? While you don't care about top speed
we need to know your lightly loaded wot gps speed and rpm. The only way to evaluate your set up.
From your description I would say a 19" pitch should help a lot but you may need to watch the rpm.

 

[timm4433]

I did not check the speed with a GPS, as I did not have anything with me to check it during my test run. I know the speedometer is not as accurate, but it was reading 38 MPH. I checked the outdrive (alpha one) and it has a gear ratio of 2.0, which i was able to verify by turning the engine and watching the prop. I won't be able to take it out on the water for at least a week, as the closest lake charges me $18 to use the boat launch, and I would rather launch for free with a slightly longer drive.

 

[steelespike]

your numbers are fairly good for a starting point.Though I think either the tach is wrong or your actually slower than 38.
Since this morning I had some second thoughts.
If you run with a heavy load often and plan to ski occasionally a 17" pitch is a better idea you will need to watch the rpm but
it will seem like a different boat.Jump on plane stay on plane easier at reduced throttle.