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  1. #1

    Impeller pitch question! Help please!!

    I recently bought a 1996 Polaris SLT 780. It needs a new impeller. I live at 6,000 feet and need suggestions on what impeller size and pitch I should be looking at. Thanks!!


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Welcome to the Hulk

    Is the engine stock?
    Cylinder compression?

    What impeller was in it (part number)?

    All impellers for your Polaris will be 148mm diameter. Somewhere on here the stock impeller charts are posted.

    I don't know whether the high altitude impeller charts are listed anywhere on here

    As a guess, the stock impeller for the SLT 750 might be a reasonable match. Your engine will be down on power due to the altitude, so the actual power might be close to a 750 at sea level.

  3. #3
    Thanks!!!

    The engine is stock and yes to the cylinder compression. The impeller that was in it is a 3 blade Polaris the part number on it is 5131457.

    So basically, this is the first jet ski that is mine so I could use all the help I can get!

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by H20chick View Post
    ...The engine is stock and yes to the cylinder compression.

    The impeller that was in it is a 3 blade Polaris the part number on it is 5131457...
    What are the compression numbers for each cylinder?
    Measure compression with throttle held wide open, all spark plugs out.

    If the engine is down on power due to internal wear or other issues, even the 'correct' impeller won't provide optimal performance.

    The key with impellers is that the impeller must match the actual engine power output to allow the engine to reach optimal power RPM without over-revving at full throttle. As engine power is reduced, the impeller must be changed to one with less pitch, to allow the engine to still reach the correct maximum RPM (usually somewhere in the mid-6000 range).

    The stock impeller for a 1996 SLT 780 (rated 90HP at sea level) was 5131371 (15-20 swirl).

    The 5131457 impeller was stock on the 700cc 1996 Hurricane and 1997+ 700cc models, rated 95HP at sea level (12-17 swirl). Somehow that seems an odd match for your engine, especially at 6,000 feet

    As I said before, the 750 impeller (80HP engine) might be a better match with the 780 engine at your altitude. Polaris made several impeller versions for the 750;
    5131035
    5131371
    5131949

    One of the impeller experts might chime in, but you have a starting point to work from.

    BTW, if you haven't done so yet, click the links below for some important maintenance info regarding your Fuji engined Polaris
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  5. #5
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Welcome to the Hulk H20chick.

    Unfortunately the book I have doesn't list a 1996 SLT 780 for high elevation. (over 5000 ft)

    But it does list a 1996 SL 780 and a SLX 780.

    The SLX 780 came with the same impeller as the SLT 780 (5131371)

    And the impeller recommended for high elevation is a 11/17 swirl (5131347)

    They also give carb setting specs to use with that too:

    Operating RPM 6375-6400

    High speed screws Mag 5/8 CEN 5/8 PTO 7/8

    Low speed screws all set to 1 1/4


    Those screw settings are OUT from a lightly seated position. (all the way closed, with the limiter caps removed)



    Just for reference, I've seen a 11/17 swirl for sale on Ebay. Pretty sure Jetski mechanic has it for sale.

  6. #6
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by xlint89 View Post
    ...the impeller recommended for high elevation is a 11/17 swirl (5131347)

    ...I've seen a 11/17 swirl for sale on Ebay...
    http://cgi.ebay.ca/Polaris-700-Virag...item2eaa0669a1


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    Click avatar for tech links/info, donation request K447's Avatar
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    Arrow Early days 1992-1996 impeller chart

    Xlint, you might find this chart interesting

    I got it from someone who was very active 'back in the day'...
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  8. #8
    Watcon's Avatar
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    Try an impeller from a Polaris SLT-700. approx 2001 model.. Part number 5132372A.
    This is an ACC (watcon gauge) 10-15 and will work well at high elevation.
    If Polaris no longer stocks it.. Call Impros for a Skat trak "long blade" 10-16. (approx $250.00).

    The #457 also came in the 785 Pro, and you are correct... Its a 12-17 pitch.

    Regards,
    Randy

  9. #9
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by Watcon View Post
    Try an impeller from a Polaris SLT-700. approx 2001 model.. Part number 5132372A.

    This is an ACC (Watcon gauge) 10-15 and will work well at high elevation...
    5132372 (without the A suffix) is listed as stock for the 2000-2004 SLH, Freedom, Virage and Virage i. $230 new from PartsPitStop

    How is it that an OEM impeller matched to the 95HP 700 domestic engine would work well at high altitude with the 90HP (sea level rated) 780 engine? How much power is expected from the 780 engine at 6000 feet altitude?

    BTW, good to see you around the forum Randy!

  10. #10
    So i've been searcing lots of different web sites looking for an impeller that will fit my jet ski with the right pitch. I'm having a very hard time finding an 11/17 or anything close. I looked at the one on ebay but i'm unsure about buying a used part. Whats the difference between the 11/17 and a 12/18? Would it just be the speed??

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