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I Love Skinny Water
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Discussion Starter · #1 ·
My motor came with a 19" prop and when I ran it I got over 40 and 5,000 rpms. Now I am trying a 17" prop and today I got to 30 with 6,000 rpms. So I pulled back to 25. What prop do I need
 

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My motor came with a 19" prop and when I ran it I got over 40 and 5,000 rpms. Now I am trying a 17" prop and today I got to 30 with 6,000 rpms. So I pulled back to 25. What prop do I need
Something doesn't sound right. You shouldn't see a 1000rpm increase and a 10mph decrease with a 2" pitch prop change. Are the props the same make and model?
 

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I Love Skinny Water
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Discussion Starter · #3 ·
I made a boo boo I looked at my aluminum prop and it says 3x14x17 that prop went 40+ at 5,000 rpms. The test SS prop I think is a Yamaha and it says 17K and it did 30 at 6,000

I hope this helps
 

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FlounderPounder
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First number is diameter, second number is pitch, third number is the number of blades.

You won't have a 19" prop on that boat. It will probably be a 13, 13.75 or possibly 14".

Are the props new?

Try a 13x17 or 13x19 3 blade prop.

The smaller diameter moves less water and allows your motor to turn easier and should achieve more RPM. Wide open you should be be somewhere around 5800. The motor has an rpm range of 5600-6200 Rpms. of If not your lugging the motor to much.

Andy
 

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I Love Skinny Water
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Discussion Starter · #5 ·
Thanks Andy I have a 14x17 SS on the way
And if that doesn't work I'll try your suggestion
 

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Brandon, FL
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Thanks Andy I have a 14x17 SS on the way
And if that doesn't work I'll try your suggestion
Don't believe it will be what you need. It is the same size as you have but you are going with a much stiffer material, move more water and the prop is significantly heavier.

GZ has it right
 

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I Love Skinny Water
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Discussion Starter · #8 ·
I have been out of town in NC taking my grandsons fishing. I ran my boat with the 17k Yamaha prop my mechanic let me use and it is too small, 31 mph at 55k. I have talked to Peter at Propco propellers and his shop is near my house. He said I need a 13 1/4 x 19 SS. So I am going to go there tomorrow. He is as former racer and knows his stuff. The cost of the prop is $280 which I think is fair
 

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I Love Skinny Water
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Discussion Starter · #9 ·
I finally ran the boat with the 13x19 SS 3 blade and it is too big, at 4,200 rpm it ran 23mph. I am taking it back to see what he says
 

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I Love microskiff.com!
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what kind of boat is it on?I have the same motor.Mines is on a 18 ft carrera flats boat which is the the same hull as a dolphin backcountry or shipoke.Mine has a pocket drive which changes things a bit. I'm running a perfect 6200 rpm wot trimmed all the way at 44 mph with a laser 2 prop 3 blade 20 pitch.You could have your motor too high or too low also. Many variables you haven't mentioned.
 

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I Love Skinny Water
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Discussion Starter · #11 ·
I have a Mavrick Master angler hull on my Off shore flats boat. The aluminum prop that came with the boat went almost 50 mph at 5400 rpm and was a 14x17
 

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I Love microskiff.com!
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I have a Mavrick Master angler hull on my Off shore flats boat. The aluminum prop that came with the boat went almost 50 mph at 5400 rpm and was a 14x17
With all do respect permit I'm confused with your comments.(master angler hull on my off shore flats boat).Im going to take it that your master angler has a df140 hp with an aluminum 14x17.If so I think you're right there..Id go with the same prop in ss and move your motor up one notch. Should get you 5600 rpm and put you in factory specs.
 

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I Love Skinny Water
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Discussion Starter · #13 ·
Thanks freak I am going tomorrow to see if he will take my new prop back for a 14x17
 

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Curmudgeon Emeritus
1996 Scout 192 Sportfish
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My Scout is obviously different than your Offshore but I'm running. 14/22 on my DF140. Just keep in mind the WOT RPM range - 6300.

Cheers
 

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I Love Skinny Water
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Discussion Starter · #15 ·
I went to Propco today and Peter the owner is going to make me a 15 that should do the job. He makes really nice props

www.propco.com

imat I bet your Scout is a lot lighter than my boat [ch128512]
 

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FlounderPounder
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I went to Propco today and Peter the owner is going to make me a 15 that should do the job. He makes really nice props

www.propco.com

imat I bet your Scout is a lot lighter than my boat [ch128512]
Your boat (unless it's waterlogged) shouldn't be that heavy. My boat is 900 pounds and its heavy for its size. Is your engine setup correctly?
 

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I Love Skinny Water
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Discussion Starter · #17 ·
Mine is about 1,100 to 1,500 then the engine 460 and gas, three batteries. So the 13x19 push it 23mph at 4,200rpm
My old aluminum 13x17 ran 48 mph at 5,400 rpm

He said the 15 will be cupped to equal 17

Peter know his props he won 11 championships racing in Australia [ch128513]
 

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FlounderPounder
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:'(
Mine is about 1,100 to 1,500 then the engine 460 and gas, three batteries. So the 13x19 push it 23mph at 4,200rpm
My old aluminum 13x17 ran 48 mph at 5,400 rpm

He said the 15 will be cupped to equal 17

Peter know his props he won 11 championships racing in Australia [ch128513]
Well, this is the same guy that told you he knew what was going on a year ago too. Obviously something is up. Even comparing apples to oranges with the stainless prop to aluminum, you shouldn't get a 1,200 rpm shift only losing 2° in pitch.

Look here are performance bulletins on the DF140. First being a boat closest to your boats weight and size. Second is a 22' Epic bay boat with a 140. Well larger than yours. And for Shitz and gigs the last boat is the large and in charge Fundeck.

These boats all run at minimum a 14x20 pitch prop. All run over 40mph (Yes even the Fundeck that Clark Griswold would own runs 40)

I am not buying what the Aussie boat racing dude is saying.







These are my thoughts if the boat can run with a 13x17 prop

A) The hull is so waterlogged the motor can't push it. I would assume if this was the case you could tell when 4 people are on it just judging how much freeboard you would lose.

B) The props you have are mis labeled or are not what said owner/prop guy said they are

C) something is internally wrong with the engine or lower unit.

D) Motor is setup way to low on the transom.

Something is out of whack with this picture.
 

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Curmudgeon Emeritus
1996 Scout 192 Sportfish
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FYI hull weight is 1300 lbs. plus DF140 weight and 54 gallons of fuel. So my boat is heavier. Fully loaded with fuel gear and anglers I run about 44-45 @ 6000rmp. Light load low fuel with myself and my son I run about 46-47 @ 6200 rpm. Conditions pending.

The Zuk runs a 14 dial prop. 13 is too small. Generally speaking due to the gear ratio the engine runs a larger dia. I tried to buy a prop from Power Tech. I ran the factor SS prop for a while and then sent them my performance numbers. We discussed my boating needs and the performance I was getting. In the end they said while they would love to sell me a prop to improve performance that the factory SS prop was performing very well.

I recommend you research a Suzuki prop from a Suzuki dealer. Or if you want a custom prop call Power Tech and ask to speak to Marcus.

Best Regards
Capt. Jan

P.S. What height is the outboard mounted to the transom?
 

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I Love Skinny Water
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Discussion Starter · #20 ·
I have no idea which hole my engine is in. My mechanic put it on. Had my gps worked I could have jacked the motor up to see if that helped but I forgot to try

I had a 200 + lb. person in the boat plus me at 159 and 2 grandson at 180 and 65. The boat is not water logged

I texted that report to my mechanic

You can look at my post on the bragging area "she's finally finished" to see the boat
 
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