Whaler Central - Boston Whaler Boat Information and Photos

Posted by Whalin88 on 03/23/12 - 2:46 PM

Hey Guys,
Lately i have had some nice weather so the tarp came off the Montauk. I went to put on a new prop and realized the new prop is different then the old. The old Prop was a 3x13 1/4x17(I think made by yamaha, unsure tho). The new prop is a Solas 3x13.5x15. What are the benefits to using the new prop with the 15pitch v.s. the old with 17pitch? And what size props are you guys running on your 90hp Yamaha 2-stroke? The engine is a 2003 if that helps. With the old prop WOT was usually between 48-5200 rpms. And is solas a good prop?

Posted by BobD on 03/24/12 - 7:09 AM

Why did you change props in the first place?

The 15" prop will have better holeshot and hold plane at a lower speed, and have less top end. The 17 may get better fuel mileage have better top end.

4800 rpms sounds too low for WOT. You should be running 5500 rpms with a light load in that boat at least. That way when you load the boat with a heavier load you are not overloading the engine.

If you could only turn 5200 rpm with a 17" prop and 90hp, I bet your engine is mounted all the way down on the transom. If so raising it will improve performance and efficiency.

Solas makes a decent aluminum prop, but it is not a high performance prop by any means.

A 90 Yamaha should push a Montauk to 42mph or so at WOT

Posted by Tom W Clark on 03/24/12 - 9:01 AM

I have no experience with any SOLAS 13-1/4" x 15" prop. I do not even know what it is you bought since you do not tell us. Most manufactures make several different models.

If you are talking propeller pitch and diameter alone, what you say is not particularly meaningful. There is far more to propeller design than just pitch and diameter. You have to discuss the brand of model of propeller being considered; they are not all the same

For a Montauk with a Yamaha 90 two stroke and its 5500 RPM reline and 2:1 gears, I recommend the Stiletto Advantage 4.25 with a DE-500 hub kit.

To get the most from this prop, the motor should be raised on the transom as high as it can go.

Posted by Whalin88 on 03/24/12 - 9:33 AM

Bob d,
Thank you for the reply, the reason for changing props is the old one is looking pretty ugly. It's worn down and needs to be reconditioned. You are right as far as the motor mounting, it is all the way down. I have considered raising the engine.
Thanks for the explaination on the pitch.

Tom W. Clark, I don't know the model of the prop because I didn't buy it, it came as a spare with the boat when I bought it 2 years ago. If I can use what I have now I'd like to, I'm short on money as I will be going to college after this summer.

Posted by Jack Jordan on 03/24/12 - 5:27 PM

Listen to Tom, go with what he says. I ran 1200 miles last year in a '63 model 16 with a Solas 13.25 x 17SS and a new TLR90, WOT was always 4800. Mount that motor 3 holes up.

Posted by Tom W Clark on 03/25/12 - 10:09 AM

Stiletto Advantage 4.25 (a.k.a. Advantage II), part # D811315

Guardian SQ-LOK Hub Kit, part # DE-500 (for Yamaha 90)