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200 EfI, rich at idle, 94 , OG03xxx sn

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  • 200 EfI, rich at idle, 94 , OG03xxx sn

    Tps voltage to hi at idle. tps adjusted full lean, air temp sensor in spec, head temp sesnor in spec, fuel press 36-38 psi, new reeds, no false air, bleed hoses and check valves ok, even tried different computer. has older 14632-A17 efi with no diagnostic plug. 12.7 running battery voltage. MAP sensor works as per service manual. no leaking injectors or fuel leaks, holds fuel pressure when off. Any Ideas?
    Could bad harness send or leak voltage from orange wire to tan/black, no pinched wires going to head temp sensor. TPS has proper ohms both directions , orange to blue , and orange to tan. open voltage 8.2 on orange from computer. can't get TPS below .35, but has approx. 7.5 volt at full throttle. Throttle shutters , lower at factory preset, upper at max open to run at all.
    Disconnect either head temp sensor or TPS and it goes way over rich and dies quicker.
    Good hot spark on all, only #3 and #5 are doing most of the work, all others to rich.

  • #2
    Have you checked compression?
    Regards
    Boats.net
    Mercury Outboard Parts
    MerCruiser Parts
    Force Outboard Parts
    Mariner Outboard Parts

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    • #3
      Hi. Compression is 135-138 all 6. pulse fuel pump rebuilt, no leaks. rechecked TPS at .245. What should manifold pressure be at idle, getting 5-7 hg if I pull 15-20 , it leans out and runs better.
      Discovered irratic fire on inner switchbox, good hot fire and then off 1or 2 seconds , timing stays solid. found low volt on blue wire . looks like a stator going bad, it gers worse as the motor heats up. swapped around switchboxes and stator wires to see which was bad.
      apparent rolling misfire at Idle.

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      • #4
        The Switchbox is the most commen ignition problems. However if you have service manual you can check the stator and trigger assembly.
        Regards
        Boats.net
        Mercury Outboard Parts
        MerCruiser Parts
        Force Outboard Parts
        Mariner Outboard Parts

        Comment


        • #5
          replaced the stator and it runs like a new motor. Old stator checks out good when cold, but breaks down when under load. never take anything for granted. even the timing pionter was 4 degrees off.
          Thanks for helping

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