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  1. #1

    Lost, looking for pointers. 1994 Polaris SL 750

    Hi all
    ok I have a 94 polaris sl 750, i had gotten it for free and the guy was an idiot!!! so he had thought it was the pto cylinder was bad and then proceed to take it apart, then i guess he lost interest so now i have it.

    anywho- what i've done:
    i have put the pto cylinder back together after cleaning it up. it has 150psi compression
    the center cylinder has 165psi
    and the mag cylinder has 145psi

    i have cleaned the carbs up by using torch tip cleaning picks on the jets

    i have done the new triple output fuel pump and all new lines from the separator to carbs and the return line to the hose barb restrictor. from that there is other new line i think the other guy did (?)
    also no autocock.

    new spark plugs and battery

    now if i missed something my bad :-/

    ok now for the question: after getting all together and out on the water strapped to the trailer still. i fired it up and it pops off great no problems go to press to WOT and it seems like it stops to rev up at like 2000-2500, and after getting in the water it doesn't seem to want to plan out cause of lack there of power.

    i heard that the reeds if bad can cause this??? but when i looked at it (like i know what i'm looking at) it seemed good to me. now i'm i need some direction..

    Pleas help

    -Chris
    Last edited by K447; 06-12-2014 at 08:26 AM.


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    ...i have cleaned the carbs up by using torch tip cleaning picks on the jets...
    Did you fully disassemble the carbs and clean them using solvent carb cleaner?

    Then rebuilt with new OEM rebuild kits?

    Is the engine actually running on all three cylinders? They get equally warm?

    How to rebuild Mikuni SBN 38 Triple Carbs

  3. #3
    Yes, I have use the carb cleaner in the gallon bucket, and yes fully disassemble, no use same gaskets as the looked in good shape, all jugs get about same temp, but doesn't feel to warm runs cooler, not like bath water yet

  4. #4
    BlueFishCrisis's Avatar
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    Typical compression on the 750 motors is 120 psi. If you're compression numbers are really that high then you will have issues running regular pump gas.

    How about a few pics of the inside?

    What do you mean you "cleaned up" the PTO cylinder?

    What condition were your head gaskets in?

    What kind of spark plugs did you install?

    Did you try working the choke when the ski wouldn't rev past 2000 RPM?
    If it responds positively to choke (by increasing RPM) you have a fuel delivery issue.
    Last edited by K447; 06-11-2014 at 07:56 AM.

  5. #5

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    fuel issue sounds to me. Your sure you got the fuel lines set correctly? And installed a restriction on the return line to ensure enough fuel to the cylinders? Out of water = no resistance. In water= lots of resistance which equals more fuel to overcome resistance. I'd start there if it was me. Fuel flow and vacuum to run pump.

  6. #6

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    Sounds fuel related to me. If you cleaned carbs I am guessing you took out the jets. Are you sure you have hi low settings set correctly? Also on new top end would suggest premix 40.1 for first tank. Something else that gets over looked a lot is the plug wires. Cut zip tie pull cap off cut about 1/8 to 1/4 inch off put cap back on and zip tie

  7. #7

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    Also as big head said did you pull restricter out of return line hose and replace? Should be inside line that come off return near the end

  8. #8

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    doah! big head, lol. Its big HAD! I chased all kinds of problems with an old 750. here is what I did, and my issues went away.
    1. replaced fuel line. Reason, many times we rebuild carbs so we assume it isn't carb related. truth is, many blends of fuel corrode the lines, especially the older stuff which MTBE fuels ate up. Or as in Polaris case, they used fuel line that was BAD long term. Used models may have dried fuel which flakes off also in the lines. Replace all the lines, its a cheap assurance.
    2. replace the suction line for the fuel pump. They get old, soft, and collapse when suction is applied, causing the pump to not operate correctly.
    3. remove the petcock if it has one, they were known to be faulty.
    4. make sure you have a fuel return flow restrictor in place. I used a barb and put a big main jet in it. Made my own. This will ensure the fuel gets to all cylinders and you don't run a lean burn on the front cylinder.
    5.rebuild the diaphragm pump, and go to a bigger unit if possible.
    6. remove plugs, turn it over and you should get fuel flow from the return line (have this disconnected) so you can see.
    If all this is done first only then would I get out the wrenches and start checking the carbs.

  9. #9

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    Lol oops sorry man.

  10. #10

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    no worries. I only get bugged by cold women, warm beer and skis that don't work on a nice summer day!

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