Yamaha prop help.

[The Next KVD]

I love my 90hp Yamaha but im somewhat have trouble finding a good prop.  The current prop on it is a 13X19 aluminum Yamaha prop that turns on my outboard at 6000rpms and pushes my boat 45.3 mph wot.  However my owners manual says that the max rpms my outboard was made for is 5500.  I've been saving to buy a stainless steel prop but i know if i get the same pitch and diameter my rpms will increase.  I've talked to my dealer who says that it won't hurt my outboard if the rpms are at this level.  So i went to the prop selector on the Mercury website and the prop it selected that i should be running is a 13.5X24 LaserII.  However when looking at my outboard it doesn't look like a prop that big would fit.  So I was wondering if I should buy a ss prop on what the dealer says and have my outboard spinning faster than what it was made for or go w/ what the Mercury website says?

Thanx for any advice.

[cart7t]

6000 RPM's won't hurt your OB but you're not maximizing the RPM's that engines turning currently.  With that kind of RPM you've got room to play and you should easily be able to push your boat into the low 50mph range.  I'd look into a 21A or 23A Turbo prop personally.  13.25 X 21 or X 23.    

[Garnet]

Look around your area for a place that has a selection of props. Marinas or prop repair place and take them out and run them.

Remember to load the boat for your use. If it's tournaments then 2 guys lots of tackle full livewells.

If they will not let you test props go to the next place.

When I buy new boats in the contract will be clause on suitable prop.

Garnet

[shortbasser]

Here is something that might work a bit better than the Mercury chart.

Take a trip to the Yamaha website and check out this section:

http://www.yamaha-motor.com/outboard/products/perfbull.aspx

You can punch in all the info from your boat and motor and get the info you need on the different prop combinations for best MPH/MPG/GPH.

I run a Skeeter with a Yamaha 200 HPDI and have called Yamaha customer service with a few questions and they were quick to answer.

Shortbasser

[George Welcome]

If you wish to know about props then go to a prop shop. More than likely a boat dealer will know little more than you about prop set up. However, it does sound like you have a bit of deficiency with that RPM. Each inch of pitch equals about 200 rpm, so moving up the pitch should make your prop bite better. As Cart7 said - 21 to 23 pitch should help but I would still head to a prop shop.