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Old 05 May 2008, 03:46   #11
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Hi Richard

My engine is mounted 3" to starboard but it still leans slightly to port with the torque of the engine when it underway. I added a set of trim tabs and it totally cured the problem. As for props I think if your looking to Gain Performance then you'll have to go for Stainless Steel. But I'm pretty sure the Max RPM for the F250 is 6000rpm and you should be propped to run as close to that as you can? I would keep lifting the engine one hole at a time untill you start to experience slip or blowout when accelerating hard or in tight turns, then drop it down one hole again. A bit time consuming but one bolt hole was worth 2-3 knots on my boat and much better cruise economy. A very basic way to check engine height is to go out with a friend driving and set the boat speed and trim to the normal cruise speed and then look over the transom. The Cavitation plate should NOT be buried in water. Getting a few splashes on it is fine but if its buried in water then it needs to come up. Hope this helps

Robbie
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Old 11 May 2008, 08:49   #12
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Yamaha have just agreed to lend me a Pro Series 23 prop to test (D = 14.5"). Should get it for next weekend.

Richard
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Old 11 May 2008, 09:07   #13
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Quote:
Originally Posted by Richard Selman View Post
The anti-ventilation plate is about 30 mm above the base of the transom.

Thats not unrealistic, .. I dont think you'll be far off the mark at that, especially as the water hitting the leg is off a flat bottom. I had a hull like that a few years ago, and engine lifting made a huge difference, but you can overdo it and sacrefice too much.. just as easily. If you are looking for higher end knots, you must run S/S though
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Old 17 May 2008, 11:52   #14
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With the Pro Series 23 on I am up to 46.7 knots. This is more like it.

Richard
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Old 17 May 2008, 12:51   #15
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Richard are many RPM are you hitting at 46 kts
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Old 18 May 2008, 01:40   #16
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5400 - 5500

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Old 18 May 2008, 08:42   #17
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That about the same as us 5600 rpm
the reason i ask is, is ant the engine suppose to rev to max rev which is 6000 rpm to get max speed etc.
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Old 18 May 2008, 09:02   #18
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That about the same as us 5600 rpm
the reason i ask is, is ant the engine suppose to rev to max rev which is 6000 rpm to get max speed etc.
No, just to within the recommended WOT range-for example mine is 4500 to 5500.
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