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Old 06-01-2015, 02:36 AM   #11
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Originally Posted by Hmaninvan View Post
I have some info. Prop size, 3 blade stainless 14x25 RH
5.7 merc alpha 1leg second generation.
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Old 06-01-2015, 02:51 AM   #12
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That's a lot of pitch in that prop.

Mercruiser has a prop calculator on their WEB page that I recommend trying.

I would think something more like 13.5 x 19
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Old 06-04-2015, 04:18 AM   #13
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Got some info. Took the boat out last night. Wide open at 4000 rpm no more left 29 miles an hour.

5.7 Alpha 1 2nd generation. I posted prop pitch eairler.

Am I over propped?
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Old 06-04-2015, 11:25 AM   #14
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Originally Posted by Hmaninvan View Post
Got some info. Took the boat out last night. Wide open at 4000 rpm no more left 29 miles an hour.

5.7 Alpha 1 2nd generation. I posted prop pitch eairler.

Am I over propped?

A WOT of 4000 is overproped as the WOT should be 4600 - 4800. Dropping pitch by one size will gain about 200 rpm.

Either a 21 or 19 inch pitch sounds a better choice.
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Old 06-10-2015, 07:21 PM   #15
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I agree. Technically the max rpm range is 4400-4800, however I agree with mmwjr, the target for 'prop tuning' should be more like 4600-4800. The closer you are to the max of 4800 the better. You definitely DO NOT want to be out of the range on either end.
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Old 06-10-2015, 07:30 PM   #16
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Mercruiser Prop Selector:

https://www.mercurymarine.com/en/us/...tor/#/step-one

You should be somewhere in the 18-20 (19-20) pitch range. Run through the propr calculator and see what you come up with.
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