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Old 01 October 2011, 13:30   #21
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Boat name: SR 5.4
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Quote:
Originally Posted by Dirk Diggler View Post
Still looks to low to me!
Same opinion!
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Old 01 October 2011, 15:06   #22
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Thanks guys, went out today and there was a big improvement but I think I may knock it up another hole as there was still a bit of splashing but no way near last time.

Engine let go again though, real pity, only one cylinder this time so managed to limp home.

Good news it she likes it so much she wants a 5.5m, so it's gone from being my toy to our toy, looks like the raggie will have to go.

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Old 01 October 2011, 15:45   #23
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Hi I would raise the engine so that the plate above the prop (anti ventilation plate) is about an inch above the bottom of the transom, you should notice quite an improvement in performance as it was very low before so would have been causing a lot of drag..
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Old 03 October 2011, 04:43   #24
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Ckeck out this link.

This is for a Verado which have quite a big set back but the anticavitation plate height is valid for all set ups.

Propping correctly & how to test props.....

There are some pictures to give you an idea of what good looks like.
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Old 03 October 2011, 05:07   #25
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Good info, thanks, I'm going to raise it again this morning.

If the anti ventilation plate is too low could this cause a problem with the cooling intake and then cause my engine to develop problems? I'm not just clutching at straws to diagnose my engine fault but me outboard engineer said it could be a possibility.
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Old 03 October 2011, 05:13   #26
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I also notice you have a reasonably raked transom. Your trim pin is in the bottom hole. To put this in prespective my old SR (and the humber) both have a transom rake similar to yours. The SR had the (non PT) engine sat on the second top hole, and I have the pin about halfway on the Merc (stops me / visiting drivers trimming in too far by accident)

Once on the plane I slowly trim out 'till the prop starts letting go & trim it back in a touch......
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Old 03 October 2011, 05:14   #27
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Originally Posted by thomas View Post
Good info, thanks, I'm going to raise it again this morning.

If the anti ventilation plate is too low could this cause a problem with the cooling intake and then cause my engine to develop problems? I'm not just clutching at straws to diagnose my engine fault but me outboard engineer said it could be a possibility.
Sounds like you need to change your outboard engineer!
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Old 03 October 2011, 06:05   #28
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Quote:
Originally Posted by Dirk Diggler View Post
Sounds like you need to change your outboard engineer!
If those were his exact words then Dirk's advice seems fair! I can't see how putting an engine deeper would cause a cooling water problem - but if this is the engine problems you refer to:

Selva/Yamaha 50hp 4stroke conking out

Then I also can't see it being related to overheating!

I wonder if he said/meant with the engine deeper in the water the back pressure in the exhaust will be higher, which can make it difficult to idle (if set up at shallower depth)? Not sure if you are THAT deep though.
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Old 03 October 2011, 06:38   #29
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Too high & the intake will be out the water, but as a good chunk of your prop will also be wrong side of the surface, it's not really going to be an issue.....

For what it's worth, here's a pic of mine at about 20 knots:

http://www.rib.net/forum/attachment....6&d=1312188943
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Old 03 October 2011, 07:12   #30
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Now my keyboard's broken!!

My engineer is pretty knowledgeable and does a lot of write ups in the mags and most people round this way can't rate him highly enough so will stick with him for now, I've had it idling perfectly in the wheely bin this morning and will try it in the water one evening this week.

I've raised it as high as I can, I think it still looks a little low compared to all the images I've seen but I've run out of holes on the bracket and transom so it will have to do, if it improved half as much as it did last time then I'll be very happy - but I will have to build up the transom to support it.

If I move the pin then how do I set the trim to know where it is - so the gauge is correct?



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