jackplate help/ raise or lower

[ilovesmallies]

96 186 champion/ 175 pro xs/ 24 fury. i put on an 8" rapid jack on it and got to test it. before the jackplate i could get 63.7 gps at 5650 rpm. now i can get 64.6 at the same rpm. my question is now i have no rooster tail as before the plate is was about the top of the cowling. also before the boat was out of the water to about the livewells when i was running but now seems in a bit more than that.my question is should i raise it a few clicks or lower it. it doesnt seemed dialed in yet. didnt have time to mess with it. it was aired out better before so i am just wondering raise or lower.


Modified by ilovesmallies at 7:06 AM 2/6/2012

[Al from Canada]

Next to no rooster tail is a good thing; the lower the rooster tail the better it's setup. A rooster tail just means that the prop is pushing water up into the air instead of straight back propelling the boat.

[ol man river]

you cannot properly set up a boat by looking at the rooster tail....quit looking at it..learn how to measure your engine height, keep track of your water pressure/rpms

check here and scroll down to see how to measure engine height .

http://www.bbcboards.net/zerothread?id=582466

[flwillie]

this is a good thing Look at some of the video on the stroker board. Some of the boats run with very little rooster tail and that's really the way ya want it.

[bassin butch]

You always start @ 3.5 pad to prop shaft and adjust from there on a Champ hull. Small rooster tail is ideal. Dont mess with any adjustments unless you have a water PSI gauge to watch.

[ilovesmallies]

bump

[ChampioNman]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by ilovesmallies &raquo;</td></tr><tr><td class="quote">bump</td></tr></table>

I guess the above answers weren't good?

[ilovesmallies]

i guess it was set at 3.5 to start when installed but it seems to be not aired out like before, just wondering if i need to raise or lower to air it out more. i understand dont look at rooster tail but think i can do better than 1 mph and it seems to be running deeper. just lookin for easy advice instead of taking it out of the water and clicking and repeating.

[bassin butch]

Aint no easy button to JP set-up.

Way too many variables in play.

[Al from Canada]

Raise it 1 click at a time (which is 1/4" on a Rapid Jack) and keep an eye on your water pressure and rpms.

[mrlawler1]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by Al from Canada &raquo;</td></tr><tr><td class="quote">Raise it 1 click at a time (which is 1/4" on a Rapid Jack) and keep an eye on your water pressure and rpms. </td></tr></table>

What he said and the best piece of info I ever got about a rooster tail was if its higher than the engine you need to do some work.......so figure you got that much to play with...not sure with champion hulls but on the bee it wasn't much more than a half inch...if its too high you'll have a bigger tail and without a pressure gauge that can get expensive...I was told engine high to lower usually meant a good setup cept for an allison or bullet. I would figure that would apply for you as well...

[GhostComanche]

Here is a post I made to a gentleman recently in the Ranger forum......................not your specific boat , but this will help you out a little. .............................RR

I know this hull like the back of my hand. The best JP setting for all out performance will be 3.25" dead on pad to center shaft. **note** ............at this setting the boat will not use very much if any positive trim when running flat out at WOT. The height of the JP will lift the hull. Hull should hook up and once hooked up (on full pad) then you can put a little trim to it to pull nose to your preference. 3.5" will do dandy also, but for all out performance the 3.25" is best.................Keep in mind that these numbers will work out better with a "known" good 3 blade prop also. Once boat is on pad, you can hit trim and when properly set up the boat will throw very little to no roostertail. this is what you are striving for...................no "tail" means that the boat is pushing the boat forward.....................faster; and not using engines energy to hold the boat up......................good luck and let us know what she does.....................................RR P.S If you go with a Fury, set pad to center at 3.5" and no higher. The Fury likes to run deeper than the Tempest or comprable 3 blade prop.................................

[Largemouthlou]

The further you go back with a motor the lower in the water the motor gets due to the angle of the transom. So recheck for the 3.5, then do like Al said and adjust up only one click at a time and retest boat for performance the way you normally will run her..

Another fact is the further back you put a motor the less positive trim you will need to raise the boat and it may even feel like the boat is running flatter at it's best speeds due to some aditional stern lift from your new set up.

[Wild Bill from Knoxville]

Start at the suggested starting point. You will have to do a test run after each adjustement. Things to watch...gps speed...and water pressure. Make note of your water preasure running straight, while in a turn, and while running in choppy water. Make your adjustments until either your speed or water pressure starts to decline. Then go back one. Your pressure will probably drop off first. But again..be sure to take note of pressure while turning and running in rough water...and not just straight out wide open. Hope this helps.

[Longrodder]

What is your current water pressure at WOT?

[ilovesmallies]

it doesnt have a water pressure gauge. the pro who put it on for me said to keep checking that a solid stream is coming out and it would be fine. i went up 2 clicks for the next time out to see if it will air out a little better. i couldnt trim it out like before.

[Al from Canada]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by ilovesmallies &raquo;</td></tr><tr><td class="quote">it doesnt have a water pressure gauge. the pro who put it on for me said to keep checking that a solid stream is coming out and it would be fine. i went up 2 clicks for the next time out to see if it will air out a little better. i couldnt trim it out like before.</td></tr></table>

I would NOT be making any changes without a water pressure gauge. And whoever put it on and said to check for a solid stream is NOT a "pro".

You run it too high and it won't be very long before you blow the motor.

[ilovesmallies]

how hard is it to put on a water pressure gauge. something i can do or should i take it in. thanks for your guys help. i just want the most out of what i got. i liked the speed gain i got but it just doesnt seemed to be dialed in correctly yet so i am asking for experienced help. before jackplate i could trim about to the livewells but now it is in to about the seats. i know that not where it should be. thanks again

[mrlawler1]

Got a buddy who ran his procraft with the motor sky high without a water gauge, and I told him its way too high and your losing water.....even though it was a steady stream of water out the engine......well a melted waterpump and luckily not a blowed engine later he fixing to get it out of the shop....needs a water pressure gauge as bad as it could possibly need anything else....that's like number one on my list...engine mechanics are not cheap and if you run it very long, good stream or not you'll need one...haven't never installed one to answer you r question though...don't think its too hard for an experiance hand...

[WarEagle24]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by ilovesmallies &raquo;</td></tr><tr><td class="quote">it doesnt have a water pressure gauge. the pro who put it on for me said to keep checking that a solid stream is coming out and it would be fine. i went up 2 clicks for the next time out to see if it will air out a little better. i couldnt trim it out like before.</td></tr></table>

This guy shouldn't be allowed to get near a boat with advice like that! Dialing in a JP for maxium speed is not a simple task because there are so many variables. The chop on the water, how the boat is loaded, prop condition, weather, etc. all play a part in the set up.