Jackplate adjustment

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stratosjoe
Posts: 34
Joined: 24 Aug 2010, 16:09
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Jackplate adjustment

Post by stratosjoe »

I bought a 16' lowe 1648 It has a 40 johnson. The guy was a river runner so he put a t-h manual jackplate on it as well as a prop skeg protector. I took it out this morning first trip it dry welled or slipped. I want to lower it but don't know how low to go. Going to take off prop protector as well. Any suggestions on height would be appreciated ,thanks Joe
Obsessed with fishing. Love my ceeegars kinda fond of good bourbon as well. :lol:

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stinkfoot
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Joined: 05 Feb 2016, 03:42
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Location: Langley, BC

Jackplate adjustment

Post by stinkfoot »

Lower it till the anti-cavitation plate is level with the bottom and see how that goes.

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Johnny
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Jackplate adjustment

Post by Johnny »

can you post some photos of your concerns ?
this is a generic drawing that floats around boating forums.
as Pappy says often - all motors are not the same configuration.
so you must find that "sweet spot" that suits your rig the best.
Cavitation Plate.jpg
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PsychoXP18CC
Posts: 116
Joined: 05 May 2013, 14:48
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Location: Kaufman, Tx

Jackplate adjustment

Post by PsychoXP18CC »

First off, only change one thing at a time, then test. Throwing everything and the kitchen sink at something before testing can often bring up other issues that you'll then need to pin down.

I'd remove the skeg protector first, then run it and see how it does.

From research I've done the consensus says a prop shaft height of 3.5-4" is usually most desirable provided your setup will maintain water pressure.

Just because it's blowing out doesn't necessarily mean it's too high, it might just be too high for that particular prop. Modifying that prop or running a different prop all together might be what's needed to get the best performance. I'm running 4" shaft height right now so my anti-cavitation plate is well above the bottom of my hull (1860 mod-v), and while I do need to have some prop work done to make it even better, my rig runs better than it ever has this way and maintains water pressure.

But I agree with the above, to give any real advice some more info is needed.
Xpress XP18CC

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stratosjoe
Posts: 34
Joined: 24 Aug 2010, 16:09
9

Jackplate adjustment

Post by stratosjoe »

I am going to take the skeg and the jackplate off. It does not have power trim and I'm too old to be trying to pull it up on lock to travel on the toter. If I had it to do all over again I would have sold the motor and bought a 25 hp in the first place. Thanks for the advice though Gentlemen
Obsessed with fishing. Love my ceeegars kinda fond of good bourbon as well. :lol:

flatboat
Posts: 337
Joined: 03 Apr 2011, 07:52
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Location: illinois & louisiana

Jackplate adjustment

Post by flatboat »

i'd start with the cav plate even with the bottom . If you are running an aluminum prop there isn't much you can do to it, in my opinion the alum prop is a spare . The stainless has more versatility and performance options and easier to solve prop issues ,ie adding and subtracting pitch and cup for optimum performance and durability

surfman
Posts: 757
Joined: 29 Dec 2011, 17:29
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Jackplate adjustment

Post by surfman »

You want the motor mounted as high as possible to reduce drag and get the best performance. I would lower it 1/2 inch at a time until it no longer slips. The jack plate also sets the motor back some so you can mount it higher than you would on a motor mounted only on the transom, depending on the jack plate set back.

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