Good prop pitch for fat guys on a 15' runabout 45hp Mercury Classic Fifty 50?

atomicteevee

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May 5, 2006
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I hope the subject says it all... bought a runabout with a beaten up 14 pitch prop, would going down as drastic to a 9 pitch help hauling our lard and our beer? The current prop has a chunk out of it and we need to scrape barnacles so obviously this boat isn't getting up to speed... thanks! Scott
 

atomicteevee

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Re: Good prop pitch for fat guys on a 15' runabout 45hp Mercury Classic Fifty 50?

I've also Seafoamed and Deep Creeped but I do need to pull the carb to clean (I think)... fuel lines look good, ball looks good. We're just need getting power at wide open throttle. Can barnacles slow down a boat that much? I am sure the answer is yes. We aren't planning on leaving it in with barnacles but we did want to test the engine out since we had to have a new switch box installed.
 

pootnic

Chief Petty Officer
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Aug 11, 2007
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Re: Good prop pitch for fat guys on a 15' runabout 45hp Mercury Classic Fifty 50?

Let me see...don't know the size of boat,where the barnacles are,how much"lard"there is and maybe you only drink a 6 pack?
I doubt you know the rpms but even without that dropping 6 in pitch is normally going over board/extreme.
You say the boat isn't getting up to speed,what is it doing?
Take all the lard out you can and give her a try.
Old boat,waterlogged foam,barnacles on boat,motor runs good...?
Give us some more info and welcome to the site>.
 

sschefer

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Nov 13, 2008
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4,530
Re: Good prop pitch for fat guys on a 15' runabout 45hp Mercury Classic Fifty 50?

Let me see...don't know the size of boat,where the barnacles are,how much"lard"there is and maybe you only drink a 6 pack?
I doubt you know the rpms but even without that dropping 6 in pitch is normally going over board/extreme.
You say the boat isn't getting up to speed,what is it doing?
Take all the lard out you can and give her a try.
Old boat,waterlogged foam,barnacles on boat,motor runs good...?
Give us some more info and welcome to the site>.

That's about the most straight up answer I've heard on here in a long time. However, the OP is clearly asking for help and that's what we should be trying to provide, not excuses for not helping..


So then, to the OP (original poster). The factory prop that came stock with the motor can be identified with a little research at the iBoats store. Once you know what that is, you can compare it to what you have now and then start trying to figure out what you need to do to get the best possible performance.

If you're boat has barnacles on the hull it's going to affect performance so haul it out and clean it up before you go any further. You don't want to go spending money on props in the boats present condition. Essentially, you want to be able to say, "OK., this is the best that this boat is ever going to be, now lets do some test runs, record speed and RPM and see if we have the correct prop or if we need to change it."
 

atomicteevee

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May 5, 2006
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Re: Good prop pitch for fat guys on a 15' runabout 45hp Mercury Classic Fifty 50?

The factory prop that came stock with the motor can be identified with a little research at the iBoats store. Once you know what that is, you can compare it to what you have now and then start trying to figure out what you need to do to get the best possible performance.

Aha, I didn't think of that. Also I know we need to post the RPM's, I will get back with that. It ran faster before we had the switch box replaced when it wasn't so barnacle-laden. It's coming back out of the water - it sat for a while until we could get a tow. I'm hoping it's not water-logged foam - that's something I never even thought about. And I expected to have my newbie ch*rry busted, I've been trolling this forum long enough. I appreciate all the replies!
 

atomicteevee

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Re: Good prop pitch for fat guys on a 15' runabout 45hp Mercury Classic Fifty 50?

Old boat,waterlogged foam,barnacles on boat,motor runs good...?

It did sit on the water for 6 weeks growing barnacles and I never even thought about the foam... thanks for the tip. I'll get back with the RPMs.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Good prop pitch for fat guys on a 15' runabout 45hp Mercury Classic Fifty 50?

Guessing, a little bit I think a 14 is too much.
i think an 11" pitch is a good start.
 

Jlawsen

Master Chief Petty Officer
Joined
Apr 22, 2012
Messages
810
Re: Good prop pitch for fat guys on a 15' runabout 45hp Mercury Classic Fifty 50?

Guessing, a little bit I think a 14 is too much.
i think an 11" pitch is a good start.

Sounds about right to me too. My 60 4 stroke runs a 12 but I keep it underpropped becuase I frequent high elevation lakes and I'm too lazy to change the prop all the time. I should be running an 11 at 6000 ft and a 13 at sea level so I settled on a 12 and called it good.

To the OP that last info is just something to think about. It'll cut your costs a little if you can find a happy medium.
 
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