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Old 06-14-2013, 06:33 PM   #1
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Default Best Prop For Mercruiser 4.3?

Im looking to put a different prop on my boat to maximize the power. What is a best size to gain some speed and or power? Im new to this stuff. I appreciate it!
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Old 06-14-2013, 07:43 PM   #2
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Call these guys. They are great to work with and very knowledgeable. They will need to know current WOT RPM's, current prop pitch / type and outdrive:

http://hillmarine.com/
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Old 06-16-2013, 06:16 AM   #3
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Call these guys. They are great to work with and very knowledgeable. They will need to know current WOT RPM's, current prop pitch / type and outdrive:

http://hillmarine.com/
Ok. I just bought the boat so I guess I need to see what the WOT RPM's are! Not sure of the prop pitch.
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Old 06-16-2013, 07:18 AM   #4
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If it's still the original prop you are running on now, keep it.
had the same question and changed a lot only to discover that the original one was the best.
if it runs wot rpm max 4200-4700 and comes in plane at about 3200 it's spot on
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Old 06-17-2013, 01:23 PM   #5
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Get the boat up to wide open throttle with the trim out as far as it can go without cavitating. Bring it out one click at a time, until it cavitates, then click down until it stops. Then look at your Max RPM.

Get the length, width, gear ratio, hp, etc. Go through the calculator to see what it comes up with.

http://www.mercurymarine.com/propellers/prop-selector/
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Old 06-17-2013, 10:20 PM   #6
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Originally Posted by rens914 View Post
If it's still the original prop you are running on now, keep it.
had the same question and changed a lot only to discover that the original one was the best.
if it runs wot rpm max 4200-4700 and comes in plane at about 3200 it's spot on
rens

Thanks for the info. You had the same boat im assuming? It just seems to not plane out and or stay planed very well. If im slow cruising 20 MPH or under it wont stay planed out very well. Never had that problem on my last boat. Havent tried to pull anybody yet.
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Old 06-17-2013, 10:22 PM   #7
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Originally Posted by shrew View Post
Get the boat up to wide open throttle with the trim out as far as it can go without cavitating. Bring it out one click at a time, until it cavitates, then click down until it stops. Then look at your Max RPM.

Get the length, width, gear ratio, hp, etc. Go through the calculator to see what it comes up with.

http://www.mercurymarine.com/propellers/prop-selector/
Thanks Shrew, ill get all that info and check that out!
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Old 06-18-2013, 07:42 AM   #8
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all great advice. mac, you have a 1800sr with a 4.3 correct? If so, you have power to spare. Take a look at your prop and tell us the numbers stamped on it. I'd be interested in knowing your prop pitch. Where do you keep your engine trimmed? I have an 1800 and get best performance with outdrive trimmed down 3/4.
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