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05 115TLRD cutting off above idle speed

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  • 05 115TLRD cutting off above idle speed

    2005 F115 TLRD w/ ~450 hrs on a 17' Edgewater that originally started having a constant ignition alarm that persisted (after turning key and while the outboard was running). I also noticed the tachometer lost its reading after going above idle speed. Tried the obvious things such as checking for lose wires, corrosion, bad grounds, etc with no improvement. Replaced the rectifier, no improvement. While troubleshooting the issue(s) the outboard started developing an issue where it would instantly cut off when going faster than idle speed. Eventually brought it to a local mechanic who hooked it up to a computer and said its flashing codes for ECM and pulser coil, so he replaced those for me.

    I got the boat back with no more ignition alarm and responsive tachometer, however the outboard continues to cut off above idle speed. The best way I can describe it is as soon as I increase on the throttle, the outboard instantly cuts off.. no bogging down, and then it is able to turn over immediately right after. I have taken the boat out multiple times in between trying "fixes" and the amount of times it cuts off varies. When I first received the boat it only happened a few times at the beginning while on the water and somehow improved to where it didn't happen at all later in the day. Following that I assumed the issue resolved so I took the boat out a couple weeks later in which the outboard would cut off at any speed above idle. It cut off 15-20 times to where I made the decision to turn around and go back to the dock at idle speed. However, by the time I got back to the dock and tried to creep up on the throttle the issue resolved itself and was operating fine for the rest of a long fishing day... put in 5 hours of fishing (with the outboard on the whole time) the rest of the day with no issues. Fast forward to yesterday and again the outboard cuts off at any speed above idle multiple times, but then turns over quickly and operates fine at idle speed.

    I originally had clogged injectors at ~150 hrs which was near 8 years ago. I got all of my injectors cleaned, VST filter replaced, and have been using non-ethanol with fuel stabilizers since then. I have been up to date on required maintenance. Between the clogged injectors @ 150 hrs and the issues im having now the outboard has ran without issue.

    I am not sure where to go from this point and I would appreciate any information/guidance from you all.

    Things I have tried/replaced so far:
    • House and cranking battery load tested
    • Rectifier
    • New ECM
    • New pulser coil
    • Checked loose connections
    • Cleaned engine grounds
    • New fuel/water separator

  • #2
    I would monitor rail pressure to see if it is running out of fuel.
    need to make sure the rail pressure stays in spec

    also turning off the key as soon as the motor dies and then draining the VST to see how much fuel is in the VST should let you know if the VST is not staying filled up.


    • #3
      Monitor the TPS reading while slowly opening the throttle. See that it does not drop out or have a dead spot. Should be smooth and linear .


      • #4
        Thank you for the suggestions thus far. I took the boat to a mechanic as this has gotten more complex than what I am capable of.

        He has communicated that he is able to reproduce the symptoms as expected. No codes on the motor. However, with his winky-blinky attached it will light up momentarily when the outboard cuts off or pops/back fires. Fuel rail pressure is good. TPS good as well. He is less concerned for a fuel issue but will be pulling the injectors and cleaning them.

        Any other suggestions?


        • #5
          Injectors cleaned and plugs replaced with no improvement