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Old 26 September 2017, 18:45   #1
eze
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Country: UK - England
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Outboard mounting height - Advise please

Boat - 4.5m Humber Assault
Engine - Merc 60 hp 4s

Outboard is for fitting tomorrow - Cavitation plate in line with bottom of transom

Any advice on height?

thanks eze
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Old 26 September 2017, 19:16   #2
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Think you're on the button with AV plate in line with bottom of transom/keel.

Pic below of our Mariner 60/XS500
Click image for larger version

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Motor elevated one hole from standard and saddle wrap over approx 20mm above top of transom to get AV plate level with keel.
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Old 26 September 2017, 19:38   #3
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Quote:
Originally Posted by chipko View Post
Think you're on the button with AV plate in line with bottom of transom/keel.

Pic below of our Mariner 60/XS500
Attachment 121994

Motor elevated one hole from standard and saddle wrap over approx 20mm above top of transom to get AV plate level with keel.
You could probably go 1 or 2 holes higher...
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Old 26 September 2017, 19:54   #4
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I'd go an inch up
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Old 27 September 2017, 00:35   #5
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Mine is mounted about 30mm higher. There's no right or wrong, it's more about what performance you are after, however if you go to high you will simply suck to much air around the prop and possibly overheat. Check this link The Outboard Expert: Boost Speed with Outboard Engine Height Adjustments - boats.com
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Old 27 September 2017, 14:20   #6
eze
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Country: UK - England
Town: Essex
Boat name: undecided
Make: Humber - Assault
Length: 4m +
Engine: Mercury 60 hp efi
MMSI: next year
Join Date: Jul 2017
Posts: 105
Engine is now fitted, we managed to use the existing holes from the merc bigfoot 25. Alignment is there or there about and we have just the one hole, should we want to go the inch higher (or whatever the distance between holes is)

Thanks for the replies guys
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Old 13 January 2018, 05:08   #7
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I would start with cavitation plate about 1 inch above the bottom of transom and see if it sucks air in turns, if it does than lower down 1 bolt hole and retest.
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