Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 28
  1. #1

    Join Date
    Apr 2008
    Location
    Ohio
    Posts
    68

    I need HELP! with my 95sl750s

    Ok so heres the deal, I had the one running great(call it pink)! after not being used for a few weeks, when I went to start it up it starts to rev out. Still sounds like its running fine just continues to climb RPM wise until i shut it off>I have no clue because the throttle is closed and all..any ideas?

    Next is my other sl750(call it black), starts up and runs but its a little boggy and when i hit the throttle, it slowly, very slowly returns to idle... im sure it all has to do with the carbs, prob needs rebuilt? is there a rebuild kit or do I have to buy everything seperate(if so what should I replace)? Thank you guys very much for your consideration, help and or ideas!


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,569
    +1
    1,272
    The usual suspect for high revving without squeezing the throttle is an air leak into the engine (intake gasket or crank shaft seal), or stuck throttle cable, stuck throttle plates.

    If it is an air leak, you do need to find and fix it, otherwise you risk engine damage from lean engine operation (too much air, not enough fuel => high piston temperatures => burned pistons)

    For the engine that slowly drops revs when the throttle is released, again check for binding or stiffness in the throttle cable and linkage. Might want to fully check and lubricate every moving part in the throttle system, from the thumb level and cable all the way to the carb throttle shafts.

    You can find info on rebuilding the Mikuni SBN carbs here, along with the Polaris PWC Service manuals.

    Rebuild kits can be purchased from several sources - only use Genuine Mikuni kits. John Zigler and Randy at www.Watcon.com are two well regarded sources.

  3. #3
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,327
    +1
    29
    Pink: Verify the throttle plates are closed fully.
    If they are, you have an air leak. You'll need to do a leak down test to find the culprit. Don't keep running it like this, otherwise you will be replacing pistons.

    Also replace the fuel hoses and filters if you haven't lately. Then clean and inspect the petcock. (also known to allow air into the fuel if the seal is bad.

    Black: Does sound like a carb rebuild is in order. You can buy 3 Mikuni Super BN 38mm rebuild kits (1 for each carb) or buy just the parts you'll need individually. Alot of parts in the kit won't be used by you as the kit also works for 44mm carbs.

    Both: Make sure that the autocock was removed from your skis. It looks like a small fuel pump, usually mounted right next to the fuel pump. It was to be removed per a Polaris service bulletin. It was known to fail and cause fuel related problems like you're having.

  4. #4

    Join Date
    Apr 2008
    Location
    Ohio
    Posts
    68
    thanks guys for the suggestions... the black boggy one I can say its carbs for sure, could you tell me what all I need for each carb for a good rebuild(obviously x 3)?

    for the other with the rev, i dont have a leak down tester so I tried something, I went ahead and switched the carbs on skis and i did the same on each just on opposite skis(making it in the carbs?) i started it up it ran good for a few secs then took off again wow am I frusteraded with these! just not much I can do with very little extra money right now

    The fix i feel like doing on both of them is pushing them off a cliff!
    hah ... thanks again for the help guys

  5. #5
    OLDJETSKIMAN's Avatar
    Join Date
    Sep 2008
    Location
    Greensboro N.C.
    Posts
    514
    +1
    1
    NO NO NO!!!!!! Great machines. Do not get frustrated!! These guys will get you thru it Take it one ski at a time. My pro ran wide open pretty sure now the air leak was the pto pluse line came off the block but went thru here any way. ( I am not rich just did a little at a time) My 95 slt750, was hard starting, fuel gauge did not work one cyl. getting hot. These guys got me thru it with some new fuel line, a 28.00 dollar triple pump from Zigler . One saturday. Now she fires and runs great. Take your time, have fun. DANG IT BOY.... GOD IS GOOD!!!!

  6. #6
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,327
    +1
    29
    What I think the bare minimum for you would be:
    (3) diaphragms
    (3) needles/seats size 2.0 push in type
    (3) shiny silver (65g) springs
    (3) seals/gaskets for back side

    Everything else you should be ok with re-using.

    All parts needed are for Mikuni Super BN 38mm carbs.


    The ski with the death rev most likely has an air leak.

    You need to methodically eliminate possible problems.

    First remove the carbs and seal the intake air-tight.

    Then remove the exhaust pipe and seal the exh manifold.

    Rent a handheld vacuum pump/brake bleeder from an autoparts store.

    Attach that to the pulse hose fitting on the block.

    Apply 9 in. of vacuum and see how long it holds for. 10 mins with dropping 1-2 in. is good. If it holds only for a minute or so, you have an air leak and need to find it, usually with soapy water.


    Report back with your findings.

  7. #7

    Join Date
    Apr 2008
    Location
    Ohio
    Posts
    68
    ok so i went out and got a vacuum pump/brake bleeder, whats the best way to seal them up air tight enough to hold a vac? iv tried tape(both on exhaust/intake) and it just doesn't seem to work because either one I have a huge leak or 2 me sealing it with tape isnt air tight(which is my guess) i didnt even get a flinch on the guage?

    also I did it again only cause i had both sets of carbs off and im was at a halt with checking vac on the one, I switch the pink high rev set to the other ski and it does the same, does that say anything? could it be something in the carbs that would do it?

    again thank you!

  8. #8
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,327
    +1
    29
    Some guys have made block off plates with anything they got laying around.

    I like to use raquette balls (walmart for $3) that are cut in half (just a hair smaller than half actually) for the intake manifold.

    I then use a whole raquette ball in the exh manifold (don't push it all the way into the pipe so you can't get it out).

    Use a little oil on the balls to help seal the opening.


    If swapping the carbs to the other ski makes that one death rev, it sounds like you need to open them up.

    Look for dry, brittle, or cracked diaphragms.
    Check the internal filters for clogs.
    Water if trapped inside the carb can block a pilot jet or leave a gunky film.

    Since you got them off, take a peak.

    OR even before that, check the low speed carb settings against the factory specs in the on line manual. And make sure the throttle plates are closed all the way.

  9. #9
    OLDJETSKIMAN's Avatar
    Join Date
    Sep 2008
    Location
    Greensboro N.C.
    Posts
    514
    +1
    1
    Quote Originally Posted by jared4brack View Post
    ok so i went out and got a vacuum pump/brake bleeder, whats the best way to seal them up air tight enough to hold a vac? iv tried tape(both on exhaust/intake) and it just doesn't seem to work because either one I have a huge leak or 2 me sealing it with tape isnt air tight(which is my guess) i didnt even get a flinch on the guage?

    also I did it again only cause i had both sets of carbs off and im was at a halt with checking vac on the one, I switch the pink high rev set to the other ski and it does the same, does that say anything? could it be something in the carbs that would do it?

    again thank you!
    Hey jared4brack, I had local ski shop test my block for 20.00 bucks. I dont know how to post it or mabe xlint can but look at my post on project skis start of pro 785 rebuild towards the end. I rebuilt my carbs over the weekend. Check out the picture of the pto filter screen next to a new one. It was full of green goo from the old fuel lines.

  10. #10
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,327
    +1
    29
    This grainy, hard to see pic????


Page 1 of 3 1 2 3 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. need help with my gprxp
    By cliff0413 in forum Conversion PWC Performance Skis
    Replies: 28
    Last Post: 08-18-2008, 05:04 PM
  2. Need help with my GP1200!
    By MTAINFLA in forum Yamaha PWC Performance (2-stroke)
    Replies: 4
    Last Post: 03-28-2008, 02:13 PM
  3. Need help with my C180
    By Atlantis in forum Sea Doo Sport Boats
    Replies: 5
    Last Post: 09-12-2007, 08:46 PM
  4. Need help with my 1050 mph
    By 1FASTXC in forum Polaris Open Discussion
    Replies: 32
    Last Post: 06-09-2007, 02:05 PM
  5. Need Help with my STLX 1050
    By Johnquest in forum Polaris Open Discussion
    Replies: 18
    Last Post: 03-15-2007, 10:01 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •