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Alpha and Bravo prop help

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Old 04-07-2004, 01:13 PM
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Default Alpha and Bravo prop help

Quick question, can you put a bravo 1 prop on a alpha drive? I don't think so but have never tried?

Second, my friend has a 21 pitch stock black prop on his 20' wellcraft 1996? open bow ski boat w/ alpha drive, and 350 mag. He currently hits the rev limiter, any suggestions on what prop he can use and get more top end?

Thanks

WILL
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Old 04-07-2004, 02:01 PM
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Same propshaft diameter/splines on both drives. You just can't run as much daimeter on an Alpha. A 21" Mirage plus sounds like a good place to start.
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Old 04-07-2004, 02:06 PM
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Since my info only goes up to 1994, it says max operating RPM is 4600 to 4800.
Your friend needs to find out what his max operating RPM range is.
If he is hitting the limiter, you first need find out what that rpm is.
The black prop is the stock aluminum prop and it will flex like crazy under load. His best bet is to switch to a stainless prop. He should start with the same pitch he has now and see if there's a difference between the aluminum and stainless. Some places will allow you borrow/rent a prop for testing purposes. It's better to do that than spend the $400-600 on a stainless prop only to find out it's the wrong one.
If a different pitch is called for, an increase of 2" pitch (21" to 23") change will drop engine RPM by 200. If his max rpm is 4800 and hitting the limiter, a 2" pitch change will drop it down to the lowest rpm allowed (4600).
In water testing should be conducted with a light fuel load, one passenger, and no gear. Try to obtain the highest rpm without hitting the limiter. This way when you add fuel, gear, and passengers it will still be in the proper rpm range.
Once he's determined the proper pitch start shopping around (E-Bay) for good deals. And don't forget to contact the prop shops advertising here on OSO for information and prices.
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Old 04-07-2004, 08:28 PM
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Thanks,

I will pass the info along

WILL
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