Thread: Johnson "70mod"

  1. #331
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    easy if you look at the box and use basic uploader button.

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    Team Member hupiveneilija's Avatar
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    Hello,
    Does anyone have picture of emulsiontube on sst60 carb?

  3. #333
    Team Member hupiveneilija's Avatar
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    Hi there,
    Been long time but have solved fuel problems.
    With Facet redtop and some regulator i now have solid 5.5psi fuel pressure. Have to use 3mm drillbit to open that plastic fuelblock and 1 t-fitting. I also drilled floatvalves from 1.6mm to 1.8mm, no problem to hold almost 8psi pressure.
    Those 1.5in carbs are working fine now. Started 1.7mm main and 1.4mm lowspeed jets. With those was fourstroking alot in middlerange when accelerating and wot was too rich, wasnt giving power properly. Changed main to 1.6mm and it cleared top alot but was little drunk in middle.
    So, changed lowspeed to 1.3mm wich took away fourstrouking in middle and made also better wot. And all the time under 3000rpms hesitation went smaller. Only little hesitation from idle wich might stump the engine but not always.


    For ignition adv i have now max 21*. Cant use more because of that smallchamber head, it start to make heat alot for piston, especially if mix is little leaner. Tried that😂

    With this setup and little prop mod acceleration is really good even with 2 on board.
    Current head isnt the best for topend i suppose because of that very wide squishband, therefore
    i have ovalport head to work with and to see how it effects on things.

    -J-

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    Team Member hupiveneilija's Avatar
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    Today
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  5. #335
    Team Member hupiveneilija's Avatar
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    With this
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  6. #336
    Team Member LittleCharger's Avatar
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    Quote Originally Posted by hupiveneilija View Post
    Today
    Niiiice!

  7. #337
    Team Member hupiveneilija's Avatar
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    Quote Originally Posted by LittleCharger View Post
    Niiiice!
    Yep, it is!
    But in the end damn rat came to town and was so hungry that ate 1 piston halfway

    That head dont do good with these rpms, too much heat!! Have to put it side and wait untill i get that ovalport head back.

    2blade definetly is not rough weather prop, felt really loose on wawes. Good prop when water is smooth.
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  8. #338
    Team Member hupiveneilija's Avatar
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    Hello, its been awhile!
    Managed to put that original block back together and have been on water few times with it.
    Its got more degrees on every port than other blocks so its little lazy under 4500rpm but after that it pulls quite good all the way to 8000. On the video its little leaner than now when on the water so that it makes good washmarks and also ign timing is lower now.
    When on plane and over 4500thou it takes speed, both 1&2 person load, to max quicker than before or so it feels😁. Today with 2, 57kn and 7800rpm srx on it.

    Its got ovalport head cut to 0.463, 1.5in carbs with 1.8mm &#3 1.9mm mains and floatvalves enlargened to 1.8mm with 5.5psi fuel pressure. Cr is ~7to1 and compreliefholes open.
    Port * ex184, tr123, bst126 and bd 30*. Tuner is sst60 length. Boyesen reeds w/o stops and stuffing. And offcourse really loose pistons😂.

    Here is short clip from tuning on a trailer: https://youtu.be/qVexDrSZiYo

    -J-
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  9. #339
    Team Member hupiveneilija's Avatar
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    Ditched that highport block off the use. Its too lazy for takeoff and dont give anything spectacular in upper range besides huge fuelconsumption.
    Following clip is for my spare ph with 0.463 head and 1.5in carbs. Throttle response is far best for now and even with little fourstroking take rpms up just like that!

    https://youtu.be/EU0uJlRyyg8

    -J-

    Going out today to test it
    Ps. its got 165to170psi
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  10. #340
    Team Member hupiveneilija's Avatar
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    Hi again!
    Now i have carbs that works properly. They changed hole thing, throtle response is better than ever before and motor runs real nice��. Under is picture of those carbs with low end airjet and mainjet, no idle jet or screw. Airjet is #33 and main 1.8mm with those feeling very strong and when buried pedal from idle it took 58kn real quick ~8000rpm. Little trimming and 59kn @8100.
    This all with my mildest block and 0.463 head.
    https://youtu.be/PSaa3iMS5iA

    Edit: #1 178 #2 175 #3 171
    Ign adv 21* @wot
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