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  1. #1

    1995 750 SLT Snorkel intake modification and triple output fuel pump install

    This has been a two year project as I have not had a lot of time to mess with this ski. This ski when I purchased it had the single outlet fuel pump and snorkel intake. I purchased the modern type flame arrestor and oilers plate. It said in the instructions to increase the the main jets in the carburetor and I did that.

    I see gas dripping in the one of the carbs so I performed a pop off and it was ok. It will run and rev on trailer but bog in the water.

    The one thing I cannot find is how to set the carburetors. These are the factory setting:
    750 - Low Speed – 1/2
    High Speed – 1m, 1/2c, 3/4p

    I am thinking it has to be more set to my 1997 780slt with the triple pump and modern spark arrestor.

    There use to be a pdf of all the factory settings for all the polaris models but I cannot find it now.

    Does anybody know what the correct carb settings should be after this mod?

    Here is the link I followed.

    https://www.shopsbt.com/forum/showthread.php?t=23527
    Last edited by WaveChaser; 07-23-2019 at 11:12 AM.

  2. #2
    Wow. Nobody?

  3. #3
    BlueFishCrisis's Avatar
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    Quote Originally Posted by WaveChaser View Post
    This has been a two year project as I have not had a lot of time to mess with this ski. This ski when I purchased it had the single outlet fuel pump and snorkel intake. I purchased the modern type flame arrestor and oilers plate. It said in the instructions to increase the the main jets in the carburetor and I did that.

    I see gas dripping in the one of the carbs so I performed a pop off and it was ok. It will run and rev on trailer but bog in the water.

    The one thing I cannot find is how to set the carburetors. These are the factory setting:
    750 - Low Speed – 1/2
    High Speed – 1m, 1/2c, 3/4p

    I am thinking it has to be more set to my 1997 780slt with the triple pump and modern spark arrestor.

    There use to be a pdf of all the factory settings for all the polaris models but I cannot find it now.

    Does anybody know what the correct carb settings should be after this mod?

    Here is the link I followed.

    https://www.shopsbt.com/forum/showthread.php?t=23527
    The kit came with larger jet sizes, and didn't suggest alternate needle settings after install.. What size jets did you install? There is never a magic carb setting, just a starting point. You need to tune manually from there.

  4. #4
    RLACEMAN's Avatar
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    Set the mixture screws to the 1996 SLT setting. The 97 had them set all the same, but used different size jets in each carb, those did run a bit better cause they were easier to tune.

  5. #5
    The jets are 102.5 mains as it only said to replace them. From what I read you start at the "stock settings" and then turn out 1/4 turn, run and check the plugs to see if they are chocolate brown and wet.
    I rebuilt the carbs including seats and float valve. the pop off pressure is around 18-20lbs. I replaced the mylar flap as well but I see fuel dripping down the throat of one carb. I have taken apart the carbs 3 times now and everything looks fine and in place. To me either with the new larger mains, I need to turn down the lows or something is not right in the carbs.

    Here are the stock settings:
    750 - Low Speed – 1/2
    High Speed – 1m, 1/2c, 3/4p

    If these are not correct settings? What should be my base settings?


  6. #6
    I am getting nowhere with this ski. I have gone through the fuel system and totally rebuilt everything:

    rebuilt carbs
    installed and rebuilt tripple output fuel pump
    installed new gas valve
    tested popoff pressure at 18lbs
    Installed 102.5 main jets in all 3 carbs per airbox modification
    Installed 1997 airbox modification.
    new rings.
    New plugs.

    Here is the issue.
    Set Low Speed – 1/2
    set High Speed - 2

    Idle machine on hose, pull plugs. Plugs are wet and sloppy.

    Put ski in water and ride around up to 1/2 throttle for a minute or two. Check plugs and plugs are white and dry.
    Start ski back up, let idle 30 sec, pull plugs, wet and sloppy again. It is obvious that it is starving for gas. I have clear gas line and there are no air bubbles in the line.

    I have read on the net where guys do the airbox mod and just open their jets more. I have changed the pump from a single output to a tripple and increased the main jet to 102.5. Do I need to increase the high jet as well? This should not be this difficult.

  7. #7
    RLACEMAN's Avatar
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    You need to ride around 15 to 30 minutes to get color on the plugs. So what exactly is the issue, its bogging on take off? You need to determine if its a lean or rich condition, if its bogging on take off & you pull out the choke a bit & it takes off its lean if it falls on its face then its rich. When you figure out which it is then procede from there. With the setting you have listed I think the low speed should be out at least 3/4 to 1 turn & the high speed should be no more than 1 1/2. Usually when changing over to this airbox the pilot jets should also be one size larger. I had a low speed bog in mine & the only way to get rid of it was larger pilot jets. Also I ask everyone with this type of problem what type of fuel are you using?

  8. #8
    With all three plugs running an aluminum color and dry just riding the ski around for a minute or two, it is running super lean and I am going to burn up the top end. This thing is starving for gas but I don't know where. I figure with the Hi out 2 turns, the plugs should be super wet or at least damp. They are dry as a bone. Only when I idle it for 30 seconds do they become wet again.

  9. #9
    xplayer2885's Avatar
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    I know this is an older thread, but have you performed a crankcase leak down test? Only asking because when I had my 750 the symptoms you are describing are similar to what I was experiencing. In my opinion I would also remove the Stator cover and check for oil buildup. This is a sure sign the front crank seal is leaking.

    hope this helps

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