Prop question again.

[setterguy]

First a little info

Motor - 2004 Yamaha 150 4 stroke. Pushing an 18' Aluminum boat.

Right now I have been running a 13 3/4 x21 and have only been getting around 4800 RPM WOT. I would like to improve the hole shot a little while gaining some RPM's. I'm assuming I will automatically get some more MPH with the increased RPM. I think I'm supposed to be way higher, in the 5500-5800 range? I know its an inexact science but anyone have a size they would start with?

[PerchJerker]

You need to drop your prop pitch to get your rpms and hole shot up. I wouldn't automatically assume you'll get more speed, but it's possible. Is it an aluminum prop you're running now? The Yamaha Pro stainless seems to be a good prop for that motor, although each boat/motor setup is a little different. You might also look at your mounting height too, if the engine can be raised a hole or two on the transom that would also help you get better performance.

[marine_man]

I agree with Dave...

Your top end RPM is 6,000, and that's what I'd be targeting to make sure you're not lugging your engine.

I'm kind of surprised that your RPM's are that low at wide open throttle, give your motor and boat setup. To get in the RPM range recommended you're talking about running a 17 pitch prop (might be able to get by with 19), which seems like a pretty flat prop for your rig.

Holeshot will be dramatically better, but your top end will go down.

Not sure if you've considered stainless, but it might be worth looking into. You will get improved holeshot and better top end, but the cost will be higher than Aluminum.

marine_man

[setterguy]

I'm not opposed to getting stainless, so do you guys think I'm Ok with my diameter?

Right now the motor is mounted on the second from the top hole. There are 4 holes so I could go up a little with the motor as well. Thanks guys.

[boatfixer]

When you go to a 17-19 pitch, the diameter is going to increase generally speaking anyway. MOST in the 17-19p range will be 14 to 14 1/4".

With the engine trimmed down, the anti-cavitation plate should be even with the keel. If it is close, leave it there.

On a side note....

Did you get this from a dealer this way? I've read several posts here from guys with newer boats saying they are at too low or too high of rpm. Are dealers really sending out these packages incorrectly propped? In the years I worked for a dealer, It was extremly rare that anything was delivered that wasnt set up right at delivery. The rigging department knew if they screwed something like pitch up, not only did they have the salesman.. (who will be the first one the customer comes looking for)..hollerin' at 'em, they also bought pizza and/or beer for everyone else.

Just something to keep in mind guys when purchasing a boat this year. Do some homework, find out what the engine should be running at. And at the time of the demo, which I would hope every dealer would do, make sure everything is running the way it should be.

[setterguy]

Ok, next question...are some stainless props better than others? There sure is a big difference in price from one to another? Am I going to notice a 150$ difference between a cabelas brand prop or a more expensive model? Thanks again guys.

[marine_man]

Sounds to me like your motor height is good.

There are a lot of differences between different stainless steel prop brands - huge infact.

I would give Jay Soderbloom a call (check out his HSOforum here: Soderblooms)

And see what he would reccomend.

As Perchjerker mentioned above, the Yamaha Pro Series Stainless props typically perform very well on a Aluminum boat with your HP motor.

You will very likely need to try a prop or two before you find the right one for your rig.

marine_man

[PerchJerker]

Setterguy - try calling your boat manufacturer, or Soderbloms, and tell them what boat and motor you have ---- they can probably narrow it down to a couple props that are likely to be the best for your setup.