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Troubleshooting Why Your Jet Ski Won’t Start Or Accelerate

There are multiple reasons why your jet ski won’t start, and although every person with a personal watercraft would like to avoid this happening, it can occur.

There is nothing worse than traveling to your holiday destination by the sea, wanting to enjoy your free time doing various water sports and your jet ski not starting.

Here are some of the most common reasons why your jet ski won’t start and how to prevent or fix the issue.

Most Common Reasons a Jet Ski Won’t Start

There are a few scenarios for why your PWC isn’t starting and we’ll go through them below.

jet ski in water

The battery is run down

This is probably one of the most common reasons why your jet ski won’t start and is often the first thing that comes to mind for most people.

If this is the reason, the first thing that you should do is to check the battery charge on the jet ski.

Worst case scenario is that you have a weak battery or bad battery that would need to be replaced with a new one.

A professional will be able to replace your dead battery with a new battery in no time.

It could also just mean that your battery needs to be charged. In this case, nothing drastic needs to be done and can simply be corrected by charging it.

A flat battery can be identified when starting the jet ski and all the system goes on and your jet ski clicks.

It is always best to charge your battery overnight so that you can avoid this from happening.

You can also use a solar panel to charge your battery.

Your jet ski may be hydro-locked

One of the most important ways to make sure that your jet ski is in good condition is to flush it.

A build-up of water inside your jet ski can be detrimental to the overall functionality of your jet ski as well as one of the main reasons for it not to start.

When your jet ski is hydro locked, the only way to fix this problem is to get it done at a reputable local dealer.

Flushing a jet ski can be done by the owner but does require some knowledge to do so as it is not an easy task.

It is best to do so before the winter season as well as after you are about to store your jet ski after using it.

2015 seadoo spark

Defective spark plugs

If your jet ski won’t start, it may be due to a problem with your spark plugs.

You can take them out to see if something is wrong or if they are wet.

The spark plugs should be brown and dry.

If one spark plug is wet, then it may be that you have a problem with the ignition on the cylinder.

Jet skis that are 2-stroke could have this problem when the engine is turned over, and it is advised to have an extra set of spark plugs on hand in this case.

Issues with battery and starter relay

The starter relay, also known as a starter solenoid, is what sends power from the starter motor to the battery.

The easiest way to know if the problem is with the starter relay is if, upon starting the jet ski, it gives off one click or when you have to press the start button multiple times before your jet ski starts.

If the battery is bad, you will only hear one click when starting the jet ski engine.

It is a simple enough task to replace the bad starter relay by yourself.

Make sure that you know the correct ways in which the battery cables should be placed, as they can cause damage to your electrical system if placed incorrectly.

If you are uncertain about how to do this or do not have the correct tools to do so, you can have it replaced by a local dealer that works at a reputable service shop.

You can find a new starter relay online or at most auto parts stores.

You should also check if you have a bad starter motor, as this could also be one of the reasons why your jet ski won’t start.

This can easily be replaced at a repair shop or in the other ways mentioned.

sea-doo spark jet ski
image: Cjp24, CC BY-SA 4.0, via Wikimedia Commons

You may have used the incorrect fuel

Jet skis run on fuel, and like every motor vehicle with an engine, it requires the fuel tank to be filled with the correct fuel.

Jet skis use common unleaded fuel and should be filled regularly, especially when you have not used your jet ski for a long time.

It is advised to add a fuel stabilizer to your tank as this will ensure that the fuel stays fresh while also removing any water that may have entered your engine compartment.

Make sure that your fuel pump is in good condition too.

The air filter could be clogged

Dirt and oil could be clogging your air filter, which can cause your engine to not start.

It is always important to check your air filter when doing a systems or maintenance check.

It is also important to note that not all jet skis have air filters.

It is mainly Yamaha and Kawasaki jet skis that have air filters to look out for.

You can unclog your air filter without needing a professional, but this should be done only if necessary.

Is your jet ski beeping?

Newer jet skis have warning systems that will tell you exactly what may be wrong.

The warning systems will show you error codes when something has malfunctioned on your jet ski.

Each mode will be indicated by different beeping sounds.

You will want to consult your owner’s manual about what the error codes and beeping sounds mean.

jet ski at beach

Make sure you are using the right key to start

Jet skis have different riding modes and therefore require that you use different keys for each mode.

Be sure to check that you are inserting the correct key when starting your jet ski, as this could be the reason why your jet ski won’t start.

Your jet ski may be locked

Your jet ski could simply just be in “lock mode”.

Some jet skis come with a remote control transmitter that can be used to unlock your jet ski.

Your jet ski should always be in “normal mode” before starting it.

Much like the beeping sounds that indicate system warnings, your jet ski will beep to indicate which mode it is in.

Always check this before starting the engine.

Starter button is broken

It could just be that your start button may be faulty or broken.

This can occur after using your jet ski over a long period.

It could be that it has just gotten worn over time or might have gotten sticky due to over-exposure to saltwater.

These can very easily be replaced, and they are inexpensive, costing around $3.

jet ski on the beach

Blown fuse

When doing your regular maintenance checks, you should always include checking your fuse box.

A blown fuse can also be the reason for many other problems.

There is also more than one fuse, so it is best to consult the owner’s manual on how to locate and fix them.

Something may be stuck inside of your jet ski

Your jet ski might have sucked something up like a rod, stick, rope, or even debris.

This can go up and cause a blockage that can lead to the pump and engine not spinning.

You do not want to flip the jet ski when something is stuck in it.

This can cause it to wedge itself even further.

You should instead turn the engine off and shake your jet ski.

Shaking it side to side might help whatever is stuck inside your jet ski to loosen and fall out.

You also do not want to take the intake grate out from under your jet ski.

It is better to remove the whole pump situated at the back of your jet ski. Do this when your jet ski is not in water.

If this is not something you feel you can do, it is best to get a professional to do it for you.

Take your watercraft to your nearest dealership and have them take out whatever is stuck instead.

Paying extra for this service will be worth it, as doing it yourself may cause more damage that can be even more expensive to repair or fix.


jet skis in ocean

Does a professional need to fix the problems?

In most cases, the reasons why your watercraft won’t start are easy fixes.

If you have the necessary tools and have a basic understanding of what to look for and make a diagnosis, you will be able to fix or repair these problems yourself.

In the case that you are uncertain or not confident in what you are doing, it will be best to visit your local dealer to repair or fix the problems.

Can all problems be fixed?

The short answer here is yes, all of the problems can be fixed.

The problems pertaining to why your jet ski will not start are most often very simple problems.

This means that for the most part you will be able to fix them yourself.

Always consult your owner’s manual for the correct processes and steps on how to fix or repair the problems.

You also would need to make sure that you have the correct tools and parts to do the repairs.

If your watercraft is new and within your warranty period, you should send it back to the manufacturer.

Less common reasons

These are just the most common reasons why your watercraft won’t start.

There are other possible reasons why that should still be kept in mind:

  • The jet ski may have sucked something up while on the water. It could be something like rocks, debris, or an excess of water.
  • Water could have infiltrated into the gas.
  • Your engine carburetor could be clogged.

Final Thoughts

Whether you have a Sea Doo or a Kawasaki, there are many common reasons your jet ski won’t start.

Your jet ski battery may need to be replaced, you may be experiencing some electrical problems, or the over-exposure to saltwater could have affected its overall functioning.

To make sure that you enjoy every possible moment on your watercraft while on that much-needed vacation make sure to check for any potential issues beforehand.

Using our guide above, you’ll have your jet ski up and running again in no time!