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Old 03-09-2015, 07:54 PM   #1
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What prop for Mercury 25hp Bigfoot motor?

Hello,
I crunched my dinghy prop and cannot read the numbers on it. I contacted Michigan Wheel and bought a 10x17 prop. The dinghy will just not get up on plane. I see sizes ranging from 10x13 to 10x17 as possible for this motor.
Anybody know what is recommended?
The dinghy is an 11' RIB.
Thanks - Henry
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Old 03-09-2015, 08:54 PM   #2
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A bigfoot 25HP Merc and a 10" dia. prop don't seem right to me. I have a standard Merc 2002 25HP short shaft 2 stroke and it turns a 10" prop as well. My perception of the 'Bigfoot' concept was bigger gear boxes and props to bite more water in high torque go slower applications. Anyway I use a 10x11 on mine. I use it for a 12' inflatable keel inflatable. As well as a 14' Jon boat. Works good all around.
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Old 03-09-2015, 11:14 PM   #3
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I agree w CC.
Probably just need less pitch.

As a side "big foot" and other "high thrust" lower units are a lot like food labeled "low salt" or "low fat". But it's not low. Just lower and only a tad at that. As per the above most have 95% as much as the usual product.

When I was shopping for outboards just several years ago I found the big foot Merc had a higher gear ratio than both the regular lower units of several Suzuki's and Evinrude's (E-tech). Don't expect miracles.
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Old 03-10-2015, 09:32 PM   #4
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I have found that the "factory" prop is a 10 7/8 x 11. The distance from the center of the shaft to the plate above is almost exactly 6".
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