Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 24
  1. #1
    Here come the smokers! OBXJeepGuy's Avatar
    Join Date
    Aug 2008
    Location
    Outer Banks, NC
    Posts
    1,393

    Carb tuning issues -With video.

    Went out today to try to tune the carbs. I am alomost there.... I found out it was idling rough because the low speed screws were turned WAY out. They had to have vibrated out, because I never put them out that far. Now I am having an issue with stumbling, and pulling to top speed slower than it should. My guess is too much fuel up top.

    Here is a not so helpful video of a short run I did today. Yes, I know I sound like a chipmunk on it.




  2. #2
    Moderator OsideBill's Avatar
    Join Date
    Mar 2006
    Location
    United States
    Posts
    11,875
    +1
    30
    What has been done to the carbs? and what is the current jetting specs? Turns out Hi Lo? need info to help

  3. #3
    Here come the smokers! OBXJeepGuy's Avatar
    Join Date
    Aug 2008
    Location
    Outer Banks, NC
    Posts
    1,393
    Jetting specs are bone stock... The lows are 1 3/4 turns out, and the highs are 1 turn out. I had the highs 1.5 turns out, and turned them in 1/4 turn for 2 different runs, making no noticable change in top speed RPM. Now they are 1 turn out as I said.

    The only thing I have "done" to the carbs is put flame arrestors on it as opposed to the stock airbox.
    I have the FPP exhaust on this ski, and FPP said there was no need to jet up.

    Factory specs are:

    Main jet :130 on front (Mag) carb, 132.5 on rear (PTO)carb
    Pilot Jet :115
    Needle & Seat : 1.5

  4. #4
    Here come the smokers! OBXJeepGuy's Avatar
    Join Date
    Aug 2008
    Location
    Outer Banks, NC
    Posts
    1,393
    This is what Factory Pipe recommends:


    CARBURETOR ADJUSTMENTS
    These carburetor recommendations are for 730 feet above sea level on a completely stock
    engine. Factory Pipe testing was performed on a stock engine with aftermarket flame
    arrestors. No claims are made by Factory Pipe for the performance, reliability or function of
    this exhaust system on a modified engine. Carburetor adjustments will vary depending on
    engine modifications, fuel, altitude and other variables. PLEASE CONSULT A QUALIFIED
    TECHNICIAN IF YOU ARE NOT FAMILIAR WITH TUNING YOUR CARBURETOR(S).
    These carburetor adjustments MUST be done prior to running the engine with this exhaust
    system. High performance engines require precise jetting, Engine damage can occur if the
    carburetors are not tuned properly.
    Note: Make sure you check the stock jets
    Main jet :130 on front (Mag) carb, 132.5 on rear (PTO)carb
    Pilot Jet :115
    High speed screw :˝ turn out from closed on front(Mag) carb, 3/4 turns out on rear (PTO)carb
    Low speed screw : 1-1/2 turns out from closed
    Needle & Seat : (stock)
    Spring : (stock)
    Timing:25 degrees at 3000 rpm

  5. #5
    Moderator OsideBill's Avatar
    Join Date
    Mar 2006
    Location
    United States
    Posts
    11,875
    +1
    30
    Factory Specs on the Screws are Low 1-5/8 out and High 3/8 out.
    FPP specs show ("stock jetting" 1-1/2 out low and 5/8 out on high)
    Attached Files Attached Files

  6. #6
    Here come the smokers! OBXJeepGuy's Avatar
    Join Date
    Aug 2008
    Location
    Outer Banks, NC
    Posts
    1,393
    So it looks as though I have too much fuel going in. I just have to take it out again tomorrow, and screw around with it some more.

    I find it odd that FPP would recommend slightly less fuel on the bottom.

    I REALLY wish I had a Tiny Tach, but don't have the money to blow on one right at the moment.

  7. #7
    Moderator OsideBill's Avatar
    Join Date
    Mar 2006
    Location
    United States
    Posts
    11,875
    +1
    30
    I am sure it has to do with the increased efficiency of the pipes.

  8. #8
    Here come the smokers! OBXJeepGuy's Avatar
    Join Date
    Aug 2008
    Location
    Outer Banks, NC
    Posts
    1,393
    Did you hear how it was stumbling on its way to top RPM? When I did that, I grabbed it wide open, and held it there. That was not easing into it like it may have sounded to some. The first low speed run I eased into it, and it jumped like it did by itself.

  9. #9
    Moderator OsideBill's Avatar
    Join Date
    Mar 2006
    Location
    United States
    Posts
    11,875
    +1
    30
    hold it at mid and high RPM's and do some plug chops if you have doubts.

  10. #10
    Mpeavler's Avatar
    Join Date
    Dec 2005
    Location
    Anderson, Indiana
    Posts
    5,155
    +1
    170
    Keep in mind that with those pipes also come a "dead" spot just prior to them jumping on the pipe and pulling hard. Your's is an extreme case and likely could be cleaned up some but, you will have that slightly Scotty.

    M

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. Carb and Compression issues with 95 750 sl
    By 750sl in forum Polaris Open Discussion
    Replies: 4
    Last Post: 09-24-2010, 06:47 PM
  2. xp 951 with wiseco 91mm CARB TUNING
    By albe_giaco in forum 2-Stroke Performance
    Replies: 3
    Last Post: 07-27-2010, 09:11 AM
  3. 785 pro, need help with carb tuning
    By billybobtucson in forum Polaris PWC Performance
    Replies: 12
    Last Post: 10-01-2009, 01:21 PM
  4. help with 96xp carb tune!!!
    By flyby9er in forum 2-Stroke Performance
    Replies: 2
    Last Post: 08-04-2007, 10:08 PM
  5. Where to start with carb tuning SL 750
    By Juscruzn in forum Polaris PWC Performance
    Replies: 1
    Last Post: 07-01-2007, 02:41 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
  •