Buy Yamaha Outboard Parts


No announcement yet.

Balancing Yamaha 40hp, 4-stroke, 3-carb outboard

  • Filter
  • Time
  • Show
Clear All
new posts

  • Balancing Yamaha 40hp, 4-stroke, 3-carb outboard

    I have a 2006, 4-stroke, Yamaha, 40-hp outboard, model F40TLR
    It has three carbs and needs balancing. badly.
    I've never done this before, and could use some pointers.

    How do I go about balancing them?

    I was thinking of purchasing Morgan's CarbTune Pro.
    Any help/advice/diagrams/etc would be greatly appreciated


  • #2
    You'll need to buy a Yamaha Outboard Manual for your motor, which has a fairly simple linq and synchronizing proceedure for the 3 carbs, which is required after removal, cleaning, etc. The manual is a darn good thing to have and study and should pay for itself many times in repairs and preventive maintenance. Good luck!


    • #3
      Robert, where would I find a shop manual?

      Many carb shops in my area insist that these carbs need to be balanced using a vaccum tube (??) but I cannot find anywhere that says such a thing. In either case, they want $150 PER CARB (!!!) just to balance!
      They're on crack.

      So all that is needed for these three carbs is a link-&-sync? That seems pretty straight-forward.

      The linkage rod connecting the three carbs together is not adjustable. The screws that adjust the carb's butterfly have not been tampered with, and all seem to open/close at the exact same time. (The adjustment screws are also marked from the factory in their original position)

      Is it possible that this carb won't even need a link-&-sync?

      I seem to get mixed feedback regarding this... I suppose the answer lies in a shop manual.
      So, where can I find one?


      • #4
        Just search for: Yamaha Outboard Manuals. If carbs were removed for replacement or cleaning then they will need to the linq and sinq procedure outlined in the book. It doesn't look all that complex to me, but my carbs have never been removed so haven't had to address this issue, so far.


        • #5
          It may be that your carbs just need to be removed and cleaned. Have you drained the float chambers to look for water or debris there. You may want to install a fuel/water seperater(Walmart $27) to keep most junk out of carbs. Good Luck!


          • #6
            Synchronizing carbs with VacuumMate digital tool

            The VacuumMate tool is recommended for Mercury dealerships (same powerhead & carbs on early 2000's Mercury 30/40 4-strokes). It has worked well for me on my personal 2003 Yamaha 40 4-stroke.
            Good info about operation here. VacuumMate, carburettor, throttle valve synchroniser and analyser by TecMate

            A thorough carb cleaning is important on Yamaha 4-stroke carbs. I would be pretty surprised that an average mechanic would get them properly cleaned on the first try and then syncronized without doing a TON of internet research on this particular motor.

            If Daggitt would post his location, maybe someone reading here could suggest a dealer or mechanic to help.