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Old 15 January 2017, 10:52   #1
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'Plume' of water from engine

I've got a Suzuki dt25 on the back of a Porter's 4.5m rib, with anti-cavitation hydrofoil fitted.

I get a noticeable plume of water off the back of the engine, even at relatively low speeds.

The engine is trimmed all the way in.

Any hints on what could cause this and what I can try to fix it?
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Old 15 January 2017, 11:21   #2
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is the cavitation plate level with the keel line mine was an inch and a half low and it caused a big roostertail
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Old 15 January 2017, 11:31   #3
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Please excuse my ignorance; what do you mean by keel line?
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Old 15 January 2017, 11:44   #4
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Maybe a picture taken with the camera at the level of the bottom of the boat showing the relationship between engine and Hull would help identify the problem
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Old 15 January 2017, 12:12   #5
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trimed in too far try two holes out.
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Old 15 January 2017, 12:53   #6
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'Plume' of water from engine

Quote:
Originally Posted by tweeds View Post
Please excuse my ignorance; what do you mean by keel line?


Something like this where av plate is in line/level with the bottom of the transom in the centre i.e. keel line extended out rearwards to outboard leg.
Click image for larger version

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As Jeff said, probably just trimmed in too far. Quick fix.
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Old 15 January 2017, 15:24   #7
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Hopefully some pictures below.....


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Old 15 January 2017, 15:26   #8
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Looking now, I realise that from the angle I took the photo it doesn't really help, but hopefully the second one does.
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Old 15 January 2017, 16:48   #9
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Quote:
Originally Posted by tweeds View Post
Looking now, I realise that from the angle I took the photo it doesn't really help, but hopefully the second one does.
Engine looks about 1.5-2 inch too low I think
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Old 15 January 2017, 17:26   #10
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Engine looks about 1.5-2 inch too low I think


I agree
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Old 15 January 2017, 17:36   #11
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Quote:
Originally Posted by jeffstevens763@g View Post
Engine looks about 1.5-2 inch too low I think


I agree with you Jeff[emoji106]
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Old 15 January 2017, 17:52   #12
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Thanks.

I'll see if trimming it out also raises it a bit first. Physically raising the engine could be a bit of a job (even just getting the old bolts off).
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Old 21 January 2017, 18:46   #13
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Trimmed it out 2 holes as Jeff suggested, and its much better.

I'll look at raising it in the future, but I'm happy enough with the improvement to focus on everything else that needs sorting for now.
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Old 22 January 2017, 16:35   #14
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Quote:
Originally Posted by tweeds View Post
Trimmed it out 2 holes as Jeff suggested, and its much better.

I'll look at raising it in the future, but I'm happy enough with the improvement to focus on everything else that needs sorting for now.
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Old 03 March 2017, 09:18   #15
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Quote:
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Trimmed it out 2 holes as Jeff suggested, and its much better.

I'll look at raising it in the future, but I'm happy enough with the improvement to focus on everything else that needs sorting for now.
Bit late here, but next time you are out (I assume you don't have power trim on that) I had my old DT25 on the second last pin for cruising, and dropped it in for when I was doing rescue boat or if the cruise was in particularly lumpy waves.


Just keep moving the pin out until it starts to let go with monotonous regularity, then drop it back one. :Thumbs:


Not sure of your transom geometry, but I had an SR4, FWIW.
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