You can run personal watercraft engines (jet skis) while out of the water. You can typically start and run for 15 seconds without any source of cooling. With a flush adapter and water hose, you can run a ski out of water up to 2 minutes since the water supply cools engine and exhaust.

If you have considered purchasing any PWC or jet ski, or specifically a WaveRunner, there are a few key things you should know about these personal watercraft and how they run. In addition to learning proper riding, you’ll want to understand some things about maintenance.

If you do need to start your jet ski outside of the water, you should only do so no longer than specified in your manual, and only when it is necessary. There are few reasons you may need to do so. 

How do Jet Skis Run?

Yamaha (Waverunner) Kawasaki (Jet Ski), and Sea Doo use similar designs to run their skis. These jet skis use water to both propel the ski and cool the engine. When running the motor out of the water, the entire engine and exhaust are not being cooled. 

These jet skis get water by using an impeller as a pump, and there is a hole in this pump for it to flow water through the engine, allowing it to cool.

If you do run your WaveRunner out of the water without proper water supply, it should be for only fifteen seconds maximum. If the jet ski is not in the water or getting a proper supply of water, the engine and exhaust are at high risk of overheating. Usually, this will cause alarms to go off, and you will be alerted of this overheating risk. 

When to Run the WaveRunner Out of Water

There are a few times that you can run a jet skit out of the water if you have a proper flushing system in place, which we will later discuss. 

However, there are times when you can run the device out of the water momentarily to ensure it is working properly. Remember that you should never run the jet ski out of the water for more than a few seconds, or you are putting the entire device at risk. 

Sometimes that you may want to start the WaveRunner momentarily to ensure it is working properly are:

  • To check that the battery is charged
  • If you are buying a used jet ski and need to ensure it will start
  • If you have not run the device in some time and need to ensure it is working
  • Before attaching it to the flushing mechanism and keeping the engine cool this way 

Flushing Your Jet Ski 

If you do need to run the WaveRunner out of the water, you should have a proper water supply in place to keep the engine and exhaust cool. You will want to consult your owner’s manual for the correct procedure on running your jet ski on the hose. If you do this process wrong, it can hydro lock your engine and cause damage. 

Because saltwater can be detrimental to your jet ski, you should flush your device after every ride, both in fresh and saltwater. Flushing will remove any salt, algae, weeds, and shells that may have entered your engine.

This prevents damage to your engine and lowers the chance of corrosion for your device.

Most modern jet skis have a hose connector that you can easily use for interior cleaning. You will simply attach your traditional garden hose to the connector before starting your engine to flush your device. However, if you have an older WaveRunner model, you will want to purchase a flush kit that comes with an adaptor.

It can be difficult to find adaptor kits for older skis now, but there are still some online that you can purchase. You will simply connect this kit and then attach your traditional garden hose the same as you would with a built-in adaptor. 

Step by Step Instructions 

To fully flush your jet ski and prepare it for the next ride, you should follow the specific steps laid out in your owner’s manual. While some models will differ, most jet skis can be flushed by following these instructions:

  1. Remove the jet ski from the water and place it on the trailer attached to your vehicle. Make sure the trailer tongue is elevated slightly. This allows gravity to work with you and can speed up the flushing process. 
  2. Connect one end of your hose to the jet ski’s flush port and the other end to your water supply hose using an adaptor if needed. 
  3. Press the ignition button and let the engine run for a few seconds and then turn on the water supply for flushing. Always start the ski first. 
  4. You can then rev the engine several times, flushing the system with fresh, clean water. This should go on for at least a few minutes and up to five minutes. 
  5. Shut off water and disconnect the hose from the ski. Give the motor a few revs. This will allow it to blow out any remaining water and ensure it is fully flushed. 
  6. To fully prepare your jet ski for the next ride, you will want to wash down the outside of the jet ski at this time and give it a quick scrub with soap. Afterward, you should dry the device with a towel or let it dry naturally in the sun. I use a Master Blaster air dryer to avoid streaks and water spots, and because it is fun. 

What to Expect If You Run Your WaveRunner Out of Water

If you do run your WaveRunner out of the water, it will not sound pleasant. Again, take care not to run your ski longer than 15 seconds. Even if you are running your device with a flush hose with the engine outside of the water, it can be very loud during this process.

It may even sound like something is terribly wrong. This is just due to lack of muffling that usually occurs when engine and exhaust are submerged.

The watercraft can even sound like metal balls rattling around in the back. This is normal, though it may be alarming for someone who has not heard it before. The rattling sound you hear is from the pump, and if it is not getting water, it is not floating which causes it to bounce around.

Most of the time you don’t need to worry about these sounds unless there is a change in nature, volume or vibration pattern. Should that happen, shut off the ski and take a look to avoid causing damage.

Final thoughts

So it’s not only possible to run a Waverunner, Jet Ski, Sea Doo or other manufacturers skis out of water, it is often necessary to do so. It allows you to check that your ski is ready to go, and is needed to maintain clean systems for longevity and steady performance.

So ride hard and flush your ski when you’re done. Stay safe out there, but do stay out there.