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  1. W

    2003 Yamaha F25 Runaway Throttle on Start

    I saw this right as I was heading out to run it again. I don't have the kind of luck where things just fix themselves. Still no runaway but another symptom: after idling for 3-5 minutes the warning buzzer goes off. The tach has markings like there should be indicators for high temp or low oil...
  2. W

    2003 Yamaha F25 Runaway Throttle on Start

    Well not exactly informative checking the timing with it running, but I am not going to complain. Started right up and the throttle didn't runaway this time. Somewhat of a fast idle at 1400rpm but it's supposed to idle high cold. Backed off to 1200rpm on its own. Reads 27 degrees BTDC. I pushed...
  3. W

    2003 Yamaha F25 Runaway Throttle on Start

    It's a setting on the timing light. It adjusts the flashes so that instead of reading different markings on the flywheel it should be the 0 degree mark with the correct setting. I got lucky guessing 10 degrees to begin with. Since the light's setting has granularity where I can measure single...
  4. W

    2003 Yamaha F25 Runaway Throttle on Start

    Timing light update: With the advance set to 10 degrees, I'm getting dead-on the 0 degree mark when I start cranking. It stays on 0 for a few seconds, then shifts over to between the 0 and 5 degree mark, on to the 5, and finally shifts and holds steady between the 5 and 10. On the black sticker...
  5. W

    2003 Yamaha F25 Runaway Throttle on Start

    You've been infinitely helpful. I found potentially-conflicting guidance that the manual should be F25X-B but have not found any definitive guidance that this one is incorrect. Based on the included reference numbers I'm fairly certain it is correct. I have not seen any depictions that make me...
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    2003 Yamaha F25 Runaway Throttle on Start

    Thanks for the reminder about grounding. I think your guess is pretty good. In the manual for a different F25 it reads like this: The manual PDF is small enough I can attach it here. I've gone through it several times praying I can find more information than I've already provided. If it's in...
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    2003 Yamaha F25 Runaway Throttle on Start

    Thanks for the input. I've got the service manual and you're exactly right. The flywheel markings are for viewing through a window in the a plastic cover to check ignition timing. There's a driven sprocket below the flywheel with its own marking. For my own peace of mind I used a borescope and...
  8. W

    2003 Yamaha F25 Runaway Throttle on Start

    I believe I owe you several beers. I need to find some better information on timing with my motor but I believe you were on the money. Considering the mark at 0 degrees is the only mark I can discern on the rotor assembly, I am assuming it is the timing mark. The angle makes it look like...
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    2003 Yamaha F25 Runaway Throttle on Start

    Based on the rate of acceleration I am pretty confident it's getting more than enough fuel and air now. It's revving like it is wide-open throttle almost immediately after starting despite being in neutral. It went to starting almost immediately and continuously accelerated. I shut it down...
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    2003 Yamaha F25 Runaway Throttle on Start

    I've been working on fixing up my 2003 Yamaha F25 ESRB that has sat for a few years. I've replaced the motor oil, fuel filter, spark plugs, and impeller. I went ahead and wrote off the old fuel system outside of the engine. Brand new tank, lines, fuel/water separator, fittings, and gas. It...
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