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  1. #1
    Member OBT's Avatar
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    Initial Jack Plate Setup tips please

    School me...

    I’m going to be getting a Manual Jack Plate for the boat. Other than bolting the jack plate to the transom, which I assume is pretty straight forward, what are the starting points for mounting the motor to the Jack Plate and what is the starting point for the Jack plate itself? (115 HP mercury Pro XS 4-Stroke)


    Start the Jack plate out at the midway point and then mount the motor in the third hole as it is now without the plate and then adjust the plate from there leaving me room to adjust up or down?

    -------------------------

    Another question… Learning curve… The new engine needs some set back and height adjustments to be dialed in. By itself, the engine was blowing out at full trim and set in the 3rd hole. I’ve dropped it to the 2nd hole and that has reduced, very nearly, the props blowing out at WOT and Full Trim. Lowering it another half a hole would probably get rid of the rest. My gut feeling is that going another “full” hole would be too much. Dropping to the second hole has lost me some rpm's and a mile per hour in speed.


    In the third hole, I was, when all was leveled and measured, it was 4 ¾ inches below the pad and I was a little surprised that it would blow out, something my old 115hp 2-Stroke, also set in the third hole, didn’t do. Shaft lengths are supposed to be the same… all so damned confusing… but I was told trimming up the new motor changes the shaft to pad distance and that’s why the prop was blowing out at WOT and full trim. Maybe there’s a greater trim range on the new engine?

    It was also mentioned that I probably needed to get it set back and into “cleaner” water.



    Will setting this jack plate, beside adding some more speed, allow me to make those smaller “fine” adjustments so I can achieve good over all, (slightly on the faster side) performance and when figuring height, will I also have to figure in the position of the engine when its trimmed up?



    Thanks
    No one can be wrong that often so it has to be deliberate.

  2. Member
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    #2
    Plate to transom is cut and dried. I would mount the engine to,plate in the middle hole,that will give you the most leeway up or down.You can definitely fine tune the height better with a plate,most folks adjust about 1/4” at a time but you can go less if needed. If you got the 4” plate,set it at 4” to start and go from there.I don’t and don’t know anyone else that considers the full trim height or angle when setting the plate. Just figure out which height works best (P to P)when trimmed level and let the other be what it may.

  3. Member OBT's Avatar
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    #3
    Quote Originally Posted by Rip Bass View Post
    Plate to transom is cut and dried. I would mount the engine to,plate in the middle hole,that will give you the most leeway up or down.You can definitely fine tune the height better with a plate,most folks adjust about 1/4” at a time but you can go less if needed. If you got the 4” plate,set it at 4” to start and go from there.I don’t and don’t know anyone else that considers the full trim height or angle when setting the plate. Just figure out which height works best (P to P)when trimmed level and let the other be what it may.
    Thanks Rip Bass. I might have just made a Jack Plate a "non" issue.

    Made several runs today with the new 20" pitch Laser II and I think I've finally reached the top performance I'm going to get and I'm very happy with it!

    Here it is: A very Light chop on the water, 1/2 tank of fuel, "All" my normal 'too much" gear, New 20" Pitch Laser II Stainless Steel prop, no jack plate, Engine mounted in 2nd hole now, down from third hole, WOT, Full up trim, Rpm's 6350-6370, right in the top range that I wanted and a top speed of 51.6 mph. The fastest that boat has gone since the first day I ran it, and at that time it was totally stripped of gear.

    The Hole shot was down to 4 seconds to planed out, another improvement. The WOT "stance" of the boat, in other words, bow lifted and boat fully running on pad felt "perfect"! Its a whole different boat and that engine is a freaking dream. Especially running at the top of it's rpm range. If the rest of Mercury's FX four strokes run like this one, than they can consider it a Home Run. Its been a hectic couple of weeks playing around with the set-up, but I now declare it... dialed in. Thanks to everyone who helped me out!
    No one can be wrong that often so it has to be deliberate.

  4. Member
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    #4
    That motor should have been mounted in the second hole from the top not the third hole from the start. You need to have some work done on the prop because it's slipping over 16% and you can get more speed.

  5. Member
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    #5
    Quote Originally Posted by Old Bass Tard View Post
    Thanks Rip Bass. I might have just made a Jack Plate a "non" issue.

    Made several runs today with the new 20" pitch Laser II and I think I've finally reached the top performance I'm going to get and I'm very happy with it!

    Here it is: A very Light chop on the water, 1/2 tank of fuel, "All" my normal 'too much" gear, New 20" Pitch Laser II Stainless Steel prop, no jack plate, Engine mounted in 2nd hole now, down from third hole, WOT, Full up trim, Rpm's 6350-6370, right in the top range that I wanted and a top speed of 51.6 mph. The fastest that boat has gone since the first day I ran it, and at that time it was totally stripped of gear.

    The Hole shot was down to 4 seconds to planed out, another improvement. The WOT "stance" of the boat, in other words, bow lifted and boat fully running on pad felt "perfect"! Its a whole different boat and that engine is a freaking dream. Especially running at the top of it's rpm range. If the rest of Mercury's FX four strokes run like this one, than they can consider it a Home Run. Its been a hectic couple of weeks playing around with the set-up, but I now declare it... dialed in. Thanks to everyone who helped me out!
    Good for you! From all the posts on here,I know it’s been a PIA for you, if you’re happy with it now,that’s all that counts. It sounds good to me too with those numbers.

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    #6
    Great numbers - Enjoy!
    Do not take your half in the middle ....

  7. Better Lucky Than Good! Casslaw's Avatar
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    #7
    If your motor isn’t shaking anymore and you are happy with the performance of your boat then you are a lucky man and got it dialed in for you!

    Personally, I would love to have a 4” jackplate to get my boat dialed in....I have a porpoising issue. Moving the motor would be so much easier with a jp! But, in my opinion, if you’re happy with that new sweet motor than I’m happy for you, I hope the BBC community helped! Good luck!
    2006 Triton SP-185, 2006 Evinrude Etec 90, PowerTech NRS3, Garmin Echomap Plus 73CV & 93SV

  8. Member OBT's Avatar
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    #8
    Quote Originally Posted by Casslaw View Post
    If your motor isn’t shaking anymore and you are happy with the performance of your boat then you are a lucky man and got it dialed in for you!

    Personally, I would love to have a 4” jackplate to get my boat dialed in....I have a porpoising issue. Moving the motor would be so much easier with a jp! But, in my opinion, if you’re happy with that new sweet motor than I’m happy for you, I hope the BBC community helped! Good luck!
    They did help and thanks to all... haven't fully given up on the 4" jack plate... one could always use a bit more performance! Maybe next year!
    No one can be wrong that often so it has to be deliberate.