# Need Help 90sho 91 Silverking



## Weck68w (May 7, 2013)

Just pulled the trigger on a Yamaha 90sho, just wondering what SS prop I should go with. Definitely going to stick with a three blade, but what diameter/pitch should I go with? Hull weighs about 800lbs I think(she’s no light weight lol). Really looking for good all around performance. Any help would be greatly appreciated.


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## EdK13 (Oct 3, 2013)

Weck68w said:


> Just pulled the trigger on a Yamaha 90sho, just wondering what SS prop I should go with. Definitely going to stick with a three blade, but what diameter/pitch should I go with? Hull weighs about 800lbs I think(she’s no light weight lol). Really looking for good all around performance. Any help would be greatly appreciated.


A starting point for you.
http://www.yamahapropselector.com/propSelector/web/inner.html


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## Capt. Moose (Dec 12, 2015)

Weck68w said:


> Just pulled the trigger on a Yamaha 90sho, just wondering what SS prop I should go with. Definitely going to stick with a three blade, but what diameter/pitch should I go with? Hull weighs about 800lbs I think(she’s no light weight lol). Really looking for good all around performance. Any help would be greatly appreciated.


What was on it before?


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## Weck68w (May 7, 2013)

Capt. Moose said:


> What was on it before?


I had a Yamaha 90hp two stroke. I have contacted Powertech and had a few conversations with the dealers mechanics. I guess the hang up is that the old motor was geared 2:1 and the new one is 2.3:1. All recommendations have been to start with a 17 pitch. I though that was a bit high... or low... however it goes, it just sounded off. The old prop was a 14 pitch?


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## flyclimber (May 22, 2016)

By rough calcs you need a 16 with the new casing. Depending on the 17 Rake you might be right on! You won't know till you have a starting point.


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## Forcefed (Aug 5, 2016)

PJ,

my old SK 16’ with a 2 stroke 90hp was spinning a Mercury lazer II 20p prop to full rpm with ease, and was under propped if the boat was light. Considering the new LU has a 2.3:1 gear ratio it should spin something similar. I’d think a 17-19p three blade would be ballpark. Unless you are talking about something hard to turn like a heavy cup 4 blade with big blade area.


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## Smackdaddy53 (Dec 31, 2012)

I’d talk to a prop shop and eliminate most of the guessing and leg work. Time is money.


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