Yamaha 300 HP HPDI - Am I getting the performance I should?

[Vestbrook]

I have a Yamaha 300HP two-stroke with a three blade Yamaha Saltwater Series II prop. It's pushing a 2008 Champion 24 BAY. I top out at 5100 RPM's and 51MPH. The good thing I see is that the RPM and MPH are virtually one-to-on up and down the throttle (i.e. 2100 rmp = 21 mph, 3100 rmp = 31 mph, etc.).

The advertised RMP range for this motor goes up to 5500 (Full Throttle Range = 4500 - 5500). Am I to interpret this to mean I'm "within range" or I'm "missing top-end performance" at 5100?

Please advise

[21XDC]

What pitch prop are you running? I bet a 22P bravo1 would really work well on that rig.

Propping that motor to 5500 is what you want... Your missing out on all areas of performance.

[Vestbrook]

Thanks 21XDC. I'll look into that prop.

[21XDC]

What pitch are you running in the Yamaha saltwater series? You may be better off just going down 2 pitches from what you have.

[spider1]

I would prop it out to 6000 that motor is still strong there. I run mine up against the limiter all the time with no ill effects with the exception of that fact that it will burn a little bit more fuel!!!

[Wayne Worthy]

I agree with spider

[Vestbrook]

OK Spider, you have my attention.

Help me understand what I should do to "prop it out to 6000", I'm all ears.

The prop I have is a 3 blade Saltwater Series II
DIA: 15
PITCH: 21

In some water conditions and with the boat trimmed out just right (I have hydralic trim-tabs), I've seen it get to 5300 RPM, but this is rare.

I'm open to suggestions on how to get improved performance here.

[spider1]

The best thing would be to give the boys a Hydro Tec a call and talk to them. They can make lost of horse power with that motor and still be dependable.
Them boys knows Yamahas!!!!

I would start to play with lots of props.

What kind of hole shot do you have now?

The bravo1 props should be a good match for that boat. They carry a load really well. I am not sure just how small of a prop that they make.

[Special K III]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Vestbrook &raquo;</TD></TR><TR><TD CLASS="quote">
The prop I have is a 3 blade Saltwater Series II
DIA: 15
PITCH: 21
</TD></TR></TABLE>

A 3-blade SWSII 21 pitch and twisting 5100 rpm's? I'd consider a 26 pitch bravo (4 blade). Everyone's got an opinion. Make sure your cav plate isn't buried underwater. Maybe you need to raise your engine up a notch??

I'd think you should be able to rev more than your getting...

[Vestbrook]

Thanks for the explanation. The pictures were helpful. Next time I'm out and on the water, I'll take a look at the position of the cavation plate.

As for trying out lots of different props, I'm perfectly willing to put in the effort, but can anyone suggest an economical way to do this? I'd rather not buy a bunch of props at $250 - $300 only to settle on one.

Maybe I'll talk with my dealer about loaners I can try....perhaps used or props with varying pitches so i can at least determine the best pitch and blade combination.

[21XDC]

The 22 Bravo1 won't help your rpms, It's the smallest they make... I thought you were running more than a 21P saltwater prop. I would look into a 19P saltwater if they make one.

I think 5800 would be better.