Results 1 to 10 of 10

Thread: sl750 94 help

  1. #1

    Join Date
    Oct 2009
    Location
    australia
    Posts
    5

    sl750 94 help

    hi ther
    new to the site have a sl750 had it twice in the water for 5-10 min both times it burnd holes in the pistons fist on the mag and then on the pto side have new fuel lines new hi flow pump dont know about the timing the jets are 107.5 mains 77.5 pilots settings is as the book have it dont know any more please helpcheers jacques


  2. #2
    Lake Mead Bum & BTLS Mark starflight's Avatar
    Join Date
    May 2007
    Location
    Boulder City, NV
    Posts
    3,364
    +1
    1
    Welcome to the Hulk!
    When you replaced all the fuel lines, did you locate and re-install the return restrictor that was in the return line near the carbs?

  3. #3

    Join Date
    Oct 2009
    Location
    australia
    Posts
    5
    Quote Originally Posted by starflight View Post
    Welcome to the Hulk!
    When you replaced all the fuel lines, did you locate and re-install the return restrictor that was in the return line near the carbs?
    yes its about an inch from the carb in the return line

  4. #4
    Lake Mead Bum & BTLS Mark starflight's Avatar
    Join Date
    May 2007
    Location
    Boulder City, NV
    Posts
    3,364
    +1
    1
    Well the oe jet sizes were 90 mains and 75 pilots, and you have 107.5 and 77.5s and are still running lean? I assume you rebuilt the carbs, and cleaned the internal filters huh? If that's the case, I'd say your engine is sucking air through a leak or leaks (may need to pressure test). Or your fuel tank vent system is suspect. The fuel pump you have, is it a triple outlet pump?

  5. #5
    Lake Mead Bum & BTLS Mark starflight's Avatar
    Join Date
    May 2007
    Location
    Boulder City, NV
    Posts
    3,364
    +1
    1
    Have you removed the auto cock, and bypassed or replaced the fuel shut off valve or checked it for leaks??

  6. #6

    Join Date
    Oct 2009
    Location
    australia
    Posts
    5
    fuel pump are a twin mikuni 65lt an hour the carbs is 2 hand of a running ski nice and clean inside no auto cock in it dont know off the vent system not sure if i have it right the piston that shit it self last i check the plug just before and it had a nice brown colour beter than the other 2 some one said its the ignator that advance the timming to far ???

  7. #7
    Lake Mead Bum & BTLS Mark starflight's Avatar
    Join Date
    May 2007
    Location
    Boulder City, NV
    Posts
    3,364
    +1
    1
    I was thinking there was a intake vent check valve on your ride, but looking at the fuel system diagram, it appears to be just an open line?


    The double fuel pump is not recommended by many. Especially if the pulse line is tee'd into both pumps. SBT had a kit that would setup another pump in addition to the original. There have been some around here with that kind of fix, and come to ask why they burn't another piston after the 2 pump fix. Most would say remove that rig and install a triple outlet pump.
    2nd hand carbs from a working ski? Looks clean? Did you open the fuel inlet side of the carbs to check the internal filters? Have you checked fuel pressure between the carbs and restrictor?
    What stage of repair is the ski in now? Can you post pictures of the burn't pistons and heads so we can see if there are any signs of detonation? Or if it was just a lean burn?

  8. #8
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,599
    +1
    1,276
    Quote Originally Posted by starflight View Post
    I was thinking there was a intake vent check valve on your ride, but looking at the fuel system diagram, it appears to be just an open line?
    It seems like Polaris kept changing the design of the vent system in the early years.

    I have suggested to others that they consider upgrading to the 1995 venting arrangement, which didn't seem to change much after 1995.

    Two separate check valves for the fuel tank (one in, and one out), and one for the oil tank.

    The few additional new parts needed are not that expensive, and you will probably never need to replace them.

    Don't buy or use old check valves. You just don't know how well they are working, or whether they will vent at the correct pressures.

    Fuel tank venting improved for 1995 models, retro-fit to older years?

  9. #9

    Join Date
    Oct 2009
    Location
    australia
    Posts
    5
    thanks for all the help i will post some pictures on monday hope i can get the ski going no jetski shop in australia wants to work on the polaris ski 's they tell me to sell its shit but i love it so beta fix it cheers jacques

  10. #10

    Join Date
    Oct 2009
    Location
    australia
    Posts
    5
    o yes the fuel pump is a twin outlet pump rate at 65 lt per hour only one pump is used

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. 94 Polaris SL750 - NEED HELP FOR MY KIDS
    By coach.mike.hodges in forum Polaris How To & FAQs
    Replies: 14
    Last Post: 06-16-2012, 06:55 AM
  2. Burnt Piston 95 SL750 Need Help
    By jasonhughes67 in forum Polaris Open Discussion
    Replies: 15
    Last Post: 03-22-2009, 11:24 PM
  3. SL750 Carb help
    By Iroc-z in forum Polaris How To & FAQs
    Replies: 26
    Last Post: 07-29-2008, 07:39 PM
  4. Now no Spark SL750 94
    By seaobin in forum Polaris Open Discussion
    Replies: 22
    Last Post: 04-25-2008, 09:51 PM
  5. 93 SL750 restrictor help
    By novanuttz in forum Polaris Open Discussion
    Replies: 5
    Last Post: 04-17-2007, 10:03 PM

Posting Permissions

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