Jump Start a Jet Ski

I’m an avid jet skier. I’ve been jetting for more than ten years every summer. I ski as far into autumn as possible, until the waves are bigger than me! Then, it’s into the garage for maintenance work until next summer.

I can’t even remember how many times I’ve had to jump start my skis. It usually happens during the winter when I work on them every few weeks. The battery simply can’t sit for that long and be expected to turn the engine over.

Jump starting has become very simple for me ever since I picked up a portable battery booster. They have several on the market now and they are reasonably priced as well! Mine cost less than $100 (at the time of this writing, 2019). The battery booster has become my constant companion.

Before I had the battery booster I had to use alternate methods to jump start the battery. I’ve jumped the ski battery using:

  1. Another free-standing battery
  2. Another jet ski or another vehicle
  3. And now, my portable battery booster (Stanley has a bad boy that I love, pictured down at the 3rd Method)

1st Method

Let’s start with the simplest method: jump starting from a free-standing battery. “Free standing” just means it’s a battery not connected to anything else. When you buy a battery new in the box, it is a free-standing battery until you put it in something.


The free-standing battery needs to have a full 12-volt charge or it won’t work. That should be obvious, because the battery with the lesser charge is going to try and drain the one with a charge.

  1. Take your red (positive) jumper cable and attach it to the free-standing battery.
  2. Do the same with the black (negative) cable.
  3. Attach the other ends of the cables respectively: red to positive and black to negative.
  4. As you can see, the free-standing battery is merely an extension of the battery in the jet ski.
  5. Start your ski as usual.
  6. Detach the jumper cables from the free-standing battery and then from the jet ski battery.

Your jet ski is fired up now!

2nd Method

Jump starting a ski from another ski or vehicle is basically the same method, basically. But jumping from a vehicle comes with serious precautions.

do not recommend this method.

First let me say, if you need to jump start your jet ski at the lake, it’s best to just go buy a new battery instead! When the ski engine stops for whatever reason out on the water, which it will, you are dead on the water. It’s not fun anymore. Just get a new battery.

If you choose to jump start at the lake—in the hope that maybe the battery just has a low charge and isn’t totally shot—do it out of the water!


Back the jet ski trailer near the water. Jump start it, and immediately back it into the water. The time it takes to jump it and back in will not harm the engine, but be quick about it! And remember, the jet ski will want to propel forward! Take this into consideration when you put it into the water running. Detaching the jet ski from the trailer without having it propel out of control can prove challenging!! I’ve never done it, but I’ve watched it. It didn’t look fun to me at all!!

Now, let’s get back to jump starting from another ski or car. Here are the steps:

  1. Place the working ski or vehicle near the dead ski, so the cables will reach, but don’t let the vehicle touch the jet ski.
  2. Attach the cables to the battery, on the car or on the jet ski with the good battery. Red to positive, black to negative.
  3. Important! On the dead battery attach the positive jumper cable to the positive on the terminal. But attach the negative cable to a source of ground such as a bolt on the engine. Usually a bolt on the engine makes for a good ground. Make sure the cables are where they won’t interfere with moving engine parts once the engine starts running.
  4. When jumping from jet ski to jet ski: You can start the jet ski with the good battery, the one you are jumping from, so that water can run through its engine while jump starting the dead jet ski battery. Running the engine without water running through it can destroy the engine within a few minutes. The other option is to jump start the dead jet ski without starting the other jet ski. If the other jet ski is not turned on, it will act like a free standing battery. A jet ski with a good battery should not have a problem starting the other jet ski and then later starting itself. Batteries can start engines multiple times on one charge.
  5. When jump starting from a vehicle: DO NOT start the engine of the vehicle. The volts that will pass from the running car to the dead battery can fry the electrical system on the jet ski! There’s already plenty of juice in that car battery, it does not need to be running to charge the ski. You can just hit the starter button once you have the cables hooked up between the car and the jet ski.
  6. Once the dead jet ski is started, remove the jumper cables from the jumper vehicle first, and then from the vehicle that has been jumped. This will reduce the chance of sparking that could start an engine fire.

Make sure that the newly jump started jet ski has water available as soon as possible. A jet ski can idle for a few minutes without water, but not for long without risking engine damage.

3rd Method


This is the easiest method.

Like I said above, my battery booster is my constant companion. These things can start anything from a jet ski to a motorcycle to a car, they are that powerful. Besides jump starting, depending on the model you purchase, they usually will have a light source and a USB attachment slot. and some have an outlet plug like a generator! Pretty cool.

Make sure the battery booster itself is charged, whether from an outlet in your home or the cigarette lighter in your car. Yeah, you can charge the battery booster off the cigarette lighter in your car! Cool again, I know.

  1. Set the charged battery booster on the jet ski where it won’t fall, for example on the front seat.
  2. Access the battery compartment on the ski.
  3. Attach the red clamp to the positive and the black clamp to the negative or another source of ground on the jet ski.
  4. Turn the dial to “On” and “Jump” (depending on the model, it may be separate dials or one dial).
  5. Press the start button on the ski. If it can, the jet ski will fire right up!
  6. Turn the battery booster off and remove the clamps, first negative and then positive.

Happy skiing!

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