Which prop do I need?

Glavini

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Jun 19, 2012
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I have a 24' pontoon boat with a Mercury 80hp motor. The motor did not come with a prop and the old motor was a 40hp so not sure I can use the same prop. On any given day we will have at least 4 adults and 4 kids. Sometimes 6 and 6. Any suggestions?
 

alldodge

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I have a 24' pontoon boat with a Mercury 80hp motor. The motor did not come with a prop and the old motor was a 40hp so not sure I can use the same prop. On any given day we will have at least 4 adults and 4 kids. Sometimes 6 and 6. Any suggestions?

The prop question is always a ruff one to start from scratch. You can use the 40hp prop and it will move the boat but the 80hp will over rev. What is the pitch of the prop which was on the 40hp?
 

alldodge

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The c2-h2-1215 appears to be a 12 1/4 x 15
The other prop comes up for a 15 spline, so if it will fit it should work, don't know the year or serial number of your motor. Here is a link which list props which are available. If the 19 fits try it to see how it works out with WOT and holes shot, need to know the rpm the motor is turning. Afterwards if it does not provide what your looking for we can advise further. I'm thinking the 19 might be a bit to high but you never know

http://boatpropellers.iboats.com/Mercury_Marine-Black_Max-Propellers/48-77346A40/ApplicationGuide/
 

Glavini

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Jun 19, 2012
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The 19 does fit so I will start with that and see where we go from there. It's a Mercury 1980 80hp motor
 

steelespike

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Apr 26, 2002
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Assuming your 80 is healthy and has a 2.00 gear ratio; an 11" prop would be a starting point.
 

Glavini

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Jun 19, 2012
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It has been fully rebuilt. I brought it out today and seemed rather slow but I'm assuming because of he larger pitch. I'm waiting in the tach harness so I can hook it up and get actual readings to go from there.
 

Glavini

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Jun 19, 2012
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I'm asking around to see if I know anyone with a smaller pitch prop that I can borrow and get some readings.
 
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