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Old 09 August 2018, 06:26   #11
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Quote:
Originally Posted by Last Tango View Post
The 150 Optimax and Mercury's F150 have different gear ratios that equate to about an inch difference in prop pitch.

The Optimax's max revs are listed as 5000 > 5600 rpm

ref RPM/Gear Ratio Reference Chart



I think you can get Laser II with even number pitches. 18" ?


If I was getting into the 5500-5600 region I’d be happy enough tbh. Seems I have a few things to check first though.
Thanks
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Old 09 August 2018, 06:49   #12
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If I was getting into the 5500-5600 region I’d be happy enough tbh. Seems I have a few things to check first though.
Thanks
My quite heavy 6m cobra with 150 Opti was right at the upper end on a 19p laser so I'm almost sure you can tweak it by checking the engine height....
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Old 09 August 2018, 08:30   #13
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I'm running a 19" Tempest on my Merc F150 6.5mtr Coastline and that's revving to 5650rpm at 44kn. (Trimmed right out and getting "twichy") and the hole shot is very impressive.....absolutely no hint of "grip" issues)

Had a Vengence on my previous engine and changed it to a Laser II. The Laser was better.
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Old 09 August 2018, 15:28   #14
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You can get your current Laser2 worked to reduce the pitch, I had a 20” Laser2 worked down to an 18” for my Humber years ago.
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Old 09 August 2018, 17:23   #15
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Time to change prop I reckon

Quote:
Originally Posted by phantom 19 View Post
You can get your current Laser2 worked to reduce the pitch, I had a 20” Laser2 worked down to an 18” for my Humber years ago.


That’s food for thought, I’m going to have a look at engine height first and try to determine if it needs raised.
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Old 10 August 2018, 11:38   #16
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Click image for larger version

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Apologies for the picture quality, would have needed four hands to hold straight edge and camera etc.

From what I can see the ‘cavitation’ plate directly above the prop is iro half an inch above the bottom of the keel.

From what I’ve read I could probably raise the engine one hole and see how that affects things.
Advice/ opinions appreciated.
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Old 10 August 2018, 13:12   #17
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Yep ,,, one hole up should be fine.
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Old 10 August 2018, 14:03   #18
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Yep ,,, one hole up should be fine.


Thanks Jeff
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Old 10 August 2018, 14:04   #19
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,,, and then you need a Rev 4
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Old 10 August 2018, 14:06   #20
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,,, and then you need a Rev 4


Oh yes!
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