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  1. #1
    Moderator DrewNJ's Avatar
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    Let's talk jetting..

    Some questions I've been tossing around in my big head...

    With everything else created equal what would be the differences between these 2 low speed jetted circuits?

    115 lows at 1.5 turns
    117.5 lows at 1 turn
    120 at .5 turns

    Again, everything else created equal..

    Anyone care to take a stab at how these 3 low setups will differ?


  2. #2
    Mpeavler's Avatar
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    Quote Originally Posted by DrewNJ View Post
    Some questions I've been tossing around in my big head...

    With everything else created equal what would be the differences between these 2 low speed jetted circuits?

    115 lows at 1.5 turns
    117.5 lows at 1 turn
    120 at .5 turns

    Again, everything else created equal..

    Anyone care to take a stab at how these 3 low setups will differ?
    Keep in mind the low speed needles are for idle only. In order to determine what you want for low speed jets...you need to go out and ride the machine and do testing by staying in the low speed circuits for 1 min then accelerating to see if it bogs....or sputters....or runs great. You can mix up you pop off pressure and low speed jets since they work together.

    It's roughly 1 jet size for 1/4 turn ... I like doing the above equation with my top speed needles. If I'm more then 1 turn out...I go up in jets. I like for it to be around .5-1 at tops to ensure enough fuel at 70% throttle...before the needles help. This helps keep that spot rich.

    M

  3. #3

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    You should adjust the carbs in the order of...

    #1 Low speed adjuster
    To adjust a smooth idle

    #2 pop off pressure
    Just off idle to 1/4 throttle in conjuction w/the low speed jet

    #3 low speed jet
    Just off idle to 1/3 throttle


    If your jets are right this is where the plug chop comes in...Make sure you havent messed with the high speed screws ....because you should start rich here. 1 1/2 is a good place to start ...if you want go out and extra 1/4 turn if you feel uncomfortable about getting ready to ride the **** out of your boat.

    Alittle off-topic but that will help you out with tuning the lows, etc.

  4. #4
    Moderator DrewNJ's Avatar
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    No disrespect guys but I'm not talking about tuning the ski to run right.

    I'm talking more "theoretical"... I know a bunch of us try to get the lows at 1 turn and the highs at 1.5 turns. Seadoo wants no turns on the highs... I have always been in the camp of trying to keep everything as close to one turn as possible...I think Novi is the same..

    I've always found 5 points jetting to be one full turn..

    Wondering if you have 3 identical ski's with only the lows different as I said in the first post, what would be different? would they run different? Idle different? Could you use the same high speed jet in all three skis?..

  5. #5
    100 MILES OF HEAVEN AND I AM SMACK IN THE MIDDLE KEYZBUM's Avatar
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    Quote Originally Posted by Mpeavler View Post
    Keep in mind the low speed needles are for idle only. M
    i was under the impression that they control till 1/4 throttle and that they DO count in the "total" fuel sent to the motor ex. lows + highs = total fuel being used by motor at wot
    THESE ARE GUESS'S AND NOT FACT just wanted to throw it out there
    hey oside any insight here
    mattman
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    +++100
    Quote Originally Posted by DrewNJ View Post
    Carb jetting is such a mystery to so many people I thought I'd throw it up as a conversation. I'm no expert but I love to learn and eventually get it figured out...

  6. #6
    Moderator DrewNJ's Avatar
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    That is true matt. One thing I found with my kids 701 motor is that it smoked like crazy with the low adjuster open 1.5 turns. Jet it up on the low and bring the adjuster down under 1 and there is significantly less smoke with no change in throttle response.

    Bump the low jet up and it affects the high speed...total jetting. I remember back from the 951 days of trying to get total jetting at 250 (or maybe it was 255..it's been awhile). There were many ways you could accomplish this and it all depended on how you rode the ski and what you were looking for..

    Carb jetting is such a mystery to so many people I thought I'd throw it up as a conversation. I'm no expert but I love to learn and eventually get it figured out...

  7. #7

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    I said mine was alittle off-topic but good somebody that stumbles into the thread

  8. #8
    Mpeavler's Avatar
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    Quote Originally Posted by KEYZBUM View Post
    i was under the impression that they control till 1/4 throttle and that they DO count in the "total" fuel sent to the motor ex. lows + highs = total fuel being used by motor at wot
    THESE ARE GUESS'S AND NOT FACT just wanted to throw it out there
    hey oside any insight here
    mattman
    ps
    +++100


    Here is a copy from the book...

  9. #9
    Mpeavler's Avatar
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