Are my RPM's in the correct range?

[Southern Style]

I have purchased a 2016 Sun Tracker 24 foot DXL Party Barge TriToon on a tandom axle trailer. Beautiful boat with ski pole, cover, and all the toys.. It has a Mercury 150 4 stroke motor that is very powerful. Its my first real pontoon, as the last one I had was a 20 foot (make the inside yourself) with a 40 hp.. What an upgrade!! Speaking to a lot of friends, they think my RPM's are a little low. The motor only has 28 hrs when I got it and run in fresh water only.. Purchased it in N. Carolina, run in fresh water lakes. The RPM's top out at 5200 when trimmed out correctly. I thought the optimum RPM's were closer to 6000. It has an Enertia 3 bladed Stainless prop (don't have numbers off the top of my head) but appears to be the stock prop... per the couple I purchased it from. They did not change the prop. Am I loosing out on 800 RPM's? Don't get me wrong, this thing goes 33 MPH with 6 people on a plain... I am happy with the performance, but also want to have the correct prop (and a little extra top end would not hurt either)..

Any assistance or thoughts would be greatly appreciated.. Be Safe

 

[Alumarine]

If it's a newer 3.0 liter I the WOT throttle range is 5000-5800.
So you are in the ball park.

 

[racerone]

Props can be confusing.-----To up the RPM you would go with 2" less pitch.-------Not all styles of boat behave the same.-----Here is a test I did years ago.on a 16" ski boat with 115 HP.-----All done under same conditions / stainless props , one after noon.------19" pitch great acceleration 5800 RPM and top speed 54 MPH.-----21" pitch , slower acceleration 5400 RPM and top speed 54 MPH-----23" pitch , very slow acceleration 4900 RPM and top speed 54 MPH-----Note the change in full throttle RPM but not top speed.

 

[Southern Style]

Hmmmmmmm.. Very nice intel... Well, I would rather have the motor running at a less RPM for fuel economy and wear and tear than to try to gain 2 MPH... I was thinking that it would gain me 8 MPH or so.. If it would be minimal, then I will leave it alone. Just wanted to make sure that there was not an underlying issue somewhere... I would not think that they would sell a boat/motor combo from the manufacturer with the incorrect pitch prop installed. Thanks a bunch for everyone's quick response..

And if that motor is in the right ballpark, then I will leave well enough alone..

Be Safe..

 

[racerone]

You need a small atomic bomb to gain 8 MPH top speed.

 

[harringtondav]

Well, I would rather have the motor running at a less RPM for fuel economy and wear and tear than to try to gain 2 MPH...

That can cut both ways. If you are over pitched, you may be overworking your motor, and loosing ground on fuel economy.

With an I/O, I believe the best practice for all around performance is to select a prop that hits max spec engine rpm at WOT. I'd guess a 4 stroke O/B is the same.

 

[Chris1956]

Those 'toons can take a lot more than 6 people. I would watch your RPM when she is loaded up with passengers, as you may want to drop pitch on the prop. The same goes if you want to pull a tube....

 

[QBhoy]

Hi
Just presuming but I’m not sure an enertia would be a stock prop on any boat.

 

[Scott Danforth]

Hmmmmmmm.. Very nice intel... Well, I would rather have the motor running at a less RPM for fuel economy and wear and tear than to try to gain 2 MPH... I was thinking that it would gain me 8 MPH or so.. If it would be minimal, then I will leave it alone. Just wanted to make sure that there was not an underlying issue somewhere... I would not think that they would sell a boat/motor combo from the manufacturer with the incorrect pitch prop installed. Thanks a bunch for everyone's quick response..

And if that motor is in the right ballpark, then I will leave well enough alone..

Be Safe..

never lug a motor.....it kills them

its a boat, no such thing as fuel economy.

you need about another 100hp for 8mph on your 'toon

 

[Marine Services of Las Vegas]

The correct way to prop a boat is to have the operator on the boat, full tank of gas and NOTHING ELSE...you want the the engine to just hit the rev limiter. for every change in pitch you should gain or lose about 250-300 rpms, aluminum 3 blade is fine.