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  1. #1
    Member ep72's Avatar
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    How to measure prop to pad.

    Borrowed from BuzzB8 in the Stratos forum.

    From top to bottom.
    1. Leveling the boat using a level on the pad.
    2. Measuring the distance from the pad to a level concrete floor.
    3. Leveling the engine. (Use the trim button and move the engine, not the boat)
    4. Measuring the distance from the center of the prop shaft to the floor. Now just subtract the prop shaft measurement from the pad measurement. For my set-up, the prop is 2.75" below the pad.
    5. This picture shows that on my boat, I can still raise the engine .75" on the jackplate by removing the mounting bolts and raising the engine on the plate.










    Stroker 21
    Mercury 250 PRO XB

    TN Bluewater dealer/rep.
    BBO

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  3. Member
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    Oct 2012
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    #2
    This set-up will work on any boat? My 02 Triton Tr20 w/ 200 efi is at 3.5 inches. Will raising my engine give me more rpm's?

  4. Member
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    Jan 2005
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    #3
    You can raise it up 1/4" at a time until you gain rpms but not speed, lose water pressure below 12lbs. 15 is better or lose bow lift. 3 1/2" is low for a older Triton as most run them 2 1/2" and higher depending on which prop you have. Tempests run higher than trophys.

  5. Member
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    Mar 2005
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    milpitas
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    #4
    I have a 2002 Tr-21 225 opti have a 25 and 26 tempest props 6 inch manual jack plate. I'm at 1 3,4 below pad with 26 currently on back 3,4 tank gas full load empty livewells I'm running 73.6 mph on GPS props worked by mark croxton and the 25 has a much better hole shot but the 26 will carry the load better.you will have to play with the pvs plugs on prop. my 26 has two empty and one large installed and my 25 has one out and two installed large. Your boat should run 68-69 with a 25 and 73-75 with a 26, hope this helps good luck. seat time is important.

  6. Member
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    Nov 2012
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    Joplin
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    #5
    I saw how to do this, went and measured. My prop shaft is 7.5 below the transom. I have a 125 merc on an aluminum 2001 nova. It will hit max rpms (5250). Top speed is 50 gps with a 20 pitch laser 2. Am I correct in calculating that I need to raise the motor 3 or 4 notches? Then go try a 22 to 24 pitch? By the way, I don't have a water gauge. Do I need to get one before I lift it? Any projection to top speed on this boat.

  7. Member
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    #6
    nova do you have an aluminum boat with a flat or shallow V bottom. If you do put the cavitation plate even with the bottom of the hull.

  8. Member
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    Jun 2004
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    La Crosse county, WI
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    #7
    These measurements are taken with the jackplate all the up correct?

  9. Member
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    May 2013
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    Lake Mead. Henderson,NV
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    #8
    Is that the 8" manual detwiler? Its adjusted by a unlocking a lock nut an then single bolt in middle? Can u explain where locking nut is?
    " A Few Good Fish"
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  10. Member
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    #9
    Tarheel on your plate you should have a nut welded to the center bolt at the top then another nut on top of the plate in the middle. If you loosen the nut on the middle plate that should allow you to turn the center bolt and raise or lower the plate.

  11. Member
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    Apr 2008
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    Pismo Beach
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    #10
    thanks got it. i will try this tomorrow

  12. Member
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    Apr 2013
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    Alabama
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    #11
    I have a 19' Stratos, 88 model, with a 200 hp Evinrude. With a 14.5 x 22 Raker 3 blade, with three (3) 3/16"air holes. The cavitation plate is 1/2" below pad, it runs about 55 mph Gps at 5500 rpm. However, the hole shot is slow, takes about a minute to get on plane (bow very high, hard to see) with trim all the way down (in). Live wells empty, 1/2 tank (12 gals) gas on left side, right side empty, 3 bats.
    Jack plate is set at 1.5 inches, with about a 6" setback. Water pressure runs about 15- 18 psi on plane, 10 at idle.
    My question is this:
    I have two extra 4 blades that came with the boat. One is a 13 3/4 x 25 Ballistic, No. 435036, Attwod (no holes) & the other is a 13 1/4 x 27, no holes, Attwood, (No. 431719). What 4 blade do I run to get a quicker plane? Pics coming...
    Best Regards & Happy Trails!
    Ed

  13. Member
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    #12
    Stratos Prop 3 blade Raker "Shooter" 14.5 X 22IMG_0674.jpgIMG_0676.jpgIMG_0678.jpgIMG_0679.jpg
    Attached Images Attached Images
    Best Regards & Happy Trails!
    Ed

  14. Member
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    #13
    Stratos Prop 4 blade, 13 3/4" X 25, BallisticIMG_0680.jpgIMG_0681.jpgIMG_0682.jpg
    Best Regards & Happy Trails!
    Ed

  15. Member
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    #14
    Stratos Props, 13 1/4 27, 4 bladeIMG_0682.jpgIMG_0684.jpgIMG_0685.jpg
    Best Regards & Happy Trails!
    Ed

  16. Member
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    #15
    Best Regards & Happy Trails!
    Ed

  17. Member
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    Feb 2014
    Location
    Lancaster SC
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    6
    #16
    I have a gambler, all pro bass team boat. It is 18.3 in length. My problem is bouncing once it is up to speed, I don't know how fast that is yet. I have lowered the motor so the plate is l with the pad. I have a 15 Johnson, the prop is 14.3 x 21 3 blade.Help me please. This is my first bass boat.

  18. Member GlennVanHoesen's Avatar
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    Oct 2009
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    Chaumont Bay NY
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    #17
    when measuring prop to pad is the jack plate all the way up or down or in the middle. And where should the motor be set on the jack plate. I have a hydro JAck plate and looking for info on what hole to mount the motor to the plate on a merc 250.
    GlennVanHoesn
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  19. Member
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    #18

    Hydrojack set up

    Quote Originally Posted by GlennVanHoesen View Post
    when measuring prop to pad is the jack plate all the way up or down or in the middle. And where should the motor be set on the jack plate. I have a hydro JAck plate and looking for info on what hole to mount the motor to the plate on a merc 250.
    Glenn,
    Do you have a gauge for your Hydrojack, and what are you reading when running at max RPM for your motor/prop and min water pressure for your engine at your current set up?
    Now, don't move your motor, and go to that reading on your gauge when measuring for your prop to pad.
    Measure for prop to pad and go up 1/4" at the time to fine tune. If you have a gauge find out what the measurement is for one digit up.
    If you need to move by alot, move your motor one hole which is 3/4".
    Keep your eyes on your water pressure for min pressure, your RPM going up and your speed down, and watch your trim for about cowl high roster tail. As your engine goes up, you will not need to trim out so much, which may give you better water pressure, unless you are too high on your set up, which in your case go down one digit, and note that number.
    Keep fine tuning and you will get your best set up.

  20. Member
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    Feb 2016
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    Maryland
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    #19
    I have a 1989 gambler183 gt wit a 90 hp mercury fourstroke on it it has a jackplate there is too much of the boat in the water when on plane do I need to raise or lower it to get more of the boat out of the water

  21. Member
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    Feb 2016
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    Missouri
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    #20
    I have a 1995 488vs Ranger with a 200 efi merc running a 25p 3 blade tempest. What is the best prop and prop/pad measurement? I'm at 4 1/2" and the boat feels like the prop is sucking to much air. 5000rpm at 49 to 51mph. The prop wants to keep twisting past 6000rpm at only 60mph. The prop as been reworked so I don't know if it is close to a factory spec. Should I have them add cup, lower motor or try different prop?

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