What prop for pontoon with 3.0l ?

[Oldpos]

I have a 2001 parti Kraft 24 foot pontoon with a mercruiser 3.0l I/0 and alpha 1 gen 2 drive. I’m new to this boat and just put in a new engine. With gps I am only able to get up to 19mph. I didn’t get to drive the boat before changing engines so I don’t know how fast it should go. My question is how fast should I be going? And what prop should I use to get the best overall performance?

also the under deck is fully skinned and toons have large and long strakes.

 

[Yegboats]

Gonna need some moreinfo.
https://forums.iboats.com/forum/gen...p-questions-and-topics/295058-read-this-first

 

[Sea Rider]

Need to know at which max wot rpm is the motor running at as usually loaded on a flat no wind straight water course. Max rpm is all, achieved speed is secondary...

Happy Boating

 

[Oldpos]

Additional info-
boat is a 2001 parti kraft 240 by Godfrey
length 24 ft weight 3400 lbs

engine is a mercruiser 3.0 lx 135 hp 1989 model

wot I truly haven’t been able to achieve but I believe that engine is 4400 rpm best speed I have gotten so far is 19mph gps. With beer cooler wife and two 11 yo kids.

current prop is aluminum with the markings 1511-155-13 which I have no idea what that means.

i have a second prop that came with the boat which is a stainless steel and is marked mercury mirage plus 48-19833 and also 15p

what prop do you recommend? I am willing to buy new also so throw out the suggestions

 

[WesNewell]

First prop is Solas Amita 13p aluminum prop. I think you have the second number wrong. Maybe it's 48-19838a46, which is a mirage plus 15p ss prop. But this doesn't help.

 

[WesNewell]

At 19 mph, you aren't that far off the max speed you should be getting. Toons aren't designed to be fast. Try the Merc prop selector.

https://www.mercurymarine.com/en/us/propellers/selector/#!/step-one

 

[Oldpos]

Thanks Wesnewl! Didn’t know there was such a calculator. I put in by length, then tried by wot , and by weight and each way gave slightly different results but still were at 14.5 to 15 inch with between a 15 and 17 degree.

so I understand this correctly if I was running with less pitch( I’m at 13 now) I would be running a lot more rpm but not gaining speed? If I change to a 15 degree I would lower my rpm? If I lower the rpm would the engine bog down before reaching wot?

 

[WesNewell]

Never owned a pontoon, so I'm far from an expert on them, still in general you want the rpm to be somewhere in between the lower value and highest value of the max rpm range of your engine with a normal load. For instance if the rpm range for your engine is 4200-4600, then 4400 would be good with a normal load planed out at wot. This all assumes that the hull (toons) are in good shape and clean. There are other factors for different types of craft, but that's my general rule.