I recently purchased a used 12-foot aluminum boat with a Yamaha 9.9 4-stroke outboard motor.

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Earlier in the week, I had started the motor a few times in the driveway (in a barrel of water) without issue. I also started the motor on the lake once today too -- it worked as expected.

It was my first time ever using a motorboat. So I'm admittedly clumsy with the motor. When I ran the motor the first time, and put it into forward gear, I was alarmed by how it lurched forward and by how fast the boat was moving. So I hit the red stop engine button. And took a minute to reflect. (For what it's worth, when I was moving around in the boat, I accidentally pulled the kill switch out, since it was clipped to my life jacket.)

Long story short, I put the kill switch back in. And tried to start the boat again. But for the life of me, I couldn't get it to start. And I still can't get it to start now that I'm back home in the driveway.

The motor worked fine until I used it on the water. That makes me think I'm making a dumb, rookie mistake.

Why won't the motor start, now that I've used it?

1 Answer 1


I got the boat started again. I'm not sure what the root cause of the problem was.

I did a few things:

  1. The kill switch key was definitely in place all this time. I had checked it previously. But what I did differently this time was pull the kill switch pin out a bit toward me, rather than just slide the kill switch key into place.

  2. Likewise, the gear shifter was in neutral all this time (it needs to be in neutral in order for it to start). I had checked it previously. But what I did differently this time was move the gear shifter into forward and reverse, forcefully, and then put it back into neutral. I did that a handful of times.

  3. I also tilted the motor all the way forward for a few minutes. Then I put it back down.

  4. When I went to start the motor this time, I made sure to pull the cord as fast & hard as I possibly could. Even more so than before.

  5. (I had also replaced the spark plugs earlier in the evening. That didn't seem to have an effect, it still wouldn't start. And the old sparkplugs looked fine [photo]. But it is still something that I changed. So I thought I'd mention it.)

And now, magically, it works.

In other words: It seems like the solution was to jiggle it.

  • 2
    This sounds very like you flooded the engine - basically you switched it off too quickly after starting it and have residual liquid fuel in the cylinders (rather than aerosol as you want). You can purge this by holding the throttle open (don't do this in "drive") and pulling the starter a few times rapidly, which flushes the fuel out the exhaust - your step 4!
    – bob1
    Commented Jun 23, 2023 at 5:05
  • @bob1 Thanks Bob. That’s very helpful.
    – User1974
    Commented Jun 23, 2023 at 12:57

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