Can someone help me with these prop #'s Please

samm835

Chief Petty Officer
Joined
Dec 12, 2006
Messages
575
OK I wanted to look to see what exact size prop I had, so i looked at it and here is what I found. D3X13.25X17R, can someone decifer these for me and make sure I am reading it correctly. If I am understanding it right I have a13.25 pitch X 17 right hand turn ....am I correct or am I way wrong? THanks for the help! Also if the pitch is 13.23 I am guessing this is the pitch the blades are, what does the second number tell me?
 

boat1010

Senior Chief Petty Officer
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Mar 10, 2009
Messages
781
Re: Can someone help me with these prop #'s Please

What I think ya have is a 13.25 inch diameter prop and it is a 17 pitch.
 

boat1010

Senior Chief Petty Officer
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Mar 10, 2009
Messages
781
Re: Can someone help me with these prop #'s Please

The pitch of a prop is telling you that with perfict conditions a 17 pitch prop will move your boat 17 inches with one revolution. So the higher the pitch the more horse power ya will need to move it. The higher the number the more top end ya will have. Low numbers will give you more hole shot and higher RPM at WOT. Hope this helps.
 

samm835

Chief Petty Officer
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Dec 12, 2006
Messages
575
Re: Can someone help me with these prop #'s Please

Thanks for the quick responses, this prop is sitting on my 1992 115hp Mariner. I purchased this motor a while back and I haven't installed it on my 24ft pontoon. The motor was on a fish skeeter, since I have tested the motor on my boat I was just thinking I might be needing a new one, since it was probally geared more for that boat type. I know I should put it on the boat then go from there, but with my friends that have almost my same set up and from what I have been reading it seems a good set up would be 14X13? Thanks
 

Silvertip

Supreme Mariner
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Sep 22, 2003
Messages
28,771
Re: Can someone help me with these prop #'s Please

A 17P prop is definitely wrong for pontoon service. 13P would be in the ballpark but only testing will tell you how close it is to being correct.
 

samm835

Chief Petty Officer
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Dec 12, 2006
Messages
575
Re: Can someone help me with these prop #'s Please

This sure as hell is going to be an expensive test....I don't remember ever seeing a place saying "try it before you buy it". If I get the 13 pitch and it doesn't work then I am stuck again with two props that dont work. You know I wont' get what I paid for on the prop even with little use. Wow sometimes you gotta love boating and the price that goes with it. Hahaha, all i can do is laugh.
 

Silvertip

Supreme Mariner
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Sep 22, 2003
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28,771
Re: Can someone help me with these prop #'s Please

You didn't read the sticky at the top of this forum titled READ THIS FIRST did you. Testing means, testing what you have "now" to establish a base line. With that data we can get you close to what you "need". Without a base liine you are essentially blind as to what the engine requires. And Yes, it is a good idea to work with a prop shop that has a try before you buy program. Just be a sport and buy from them when you find what you need.
 

samm835

Chief Petty Officer
Joined
Dec 12, 2006
Messages
575
Re: Can someone help me with these prop #'s Please

Oh I did read the sticky, but I already know in advance the current prop set up isn't correct......so then I gotta go buy one and test from there. I called my local shop they don't "try it before buy it" deal. So that is why you do the next best thing. You always ask people you know or people online who have close to your set up. Easier and a hell of a lot less expensive to ask prior to buying.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Can someone help me with these prop #'s Please

I think you are misunderstanding what testing involves. I'm not suggesting you buy another prop and test it. The object is quite the opposite. You want to test what you have now -- as in obtain WOT RPM and speed numbers with what you consider an average load. From that baseline it can be determined (with reasonable accuracy) what you "actually need in a prop". With that process you get close. Just buying another prop will guarantee that you pop for the wrong one which we are trying to avoid. Buying a prop based on what someone else has is risky because unless they have the same exact boat, same exact engine, in exactly the same setup, and the engine is in exactly the same condition, prop requirements will be different. And by the way, just because someone tells you they run a 13P prop (or any other for that matter) does not mean it will work best for you because every prop manufacturer has different design critera for their props. Therefore, a 13P aluminum prop from Michigan may not and generally will not perform exactly the same as a 13P aluminum prop from Hustler for example. The only similarity is they are both 13P and probably painted black. Prop selection is partially a crap shoot -- but you can reduce the risk with proper testing.
 
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