common jet ski problems and their fixes rpx on fire

If you own a jet ski or are thinking of purchasing a new or secondhand personal watercraft you have to be aware of some of the common jet-ski problems and their fixes.

This way you can save yourself time and money from having to go to a Jet-ski repair shop for something simple. So let’s check out some problems I have come across either on my PWC or others out on the water.

How to repair your Jetski yourself

Many common problems occur out on the water and that’s the last place you would want to be repairing your personal watercraft. Make sure you have the following tools on hand in the front storage compartment of your Jetski just for emergencies.

  • Sharp long knife
  • 3/8 Drive socket set
  • Shifter or wrench
  • Screwdriver
  • Torch
  • 40cm long metal poking rod
  • Tow rope and shackle
  • Pocket Jump Starter
  • Cooper Anchor and rope
  • Water and spare life jacket.
  • Fire extinguisher.

Jet ski rope stuck intake grate or wrapped around the main shaft.

rope wrapped around jet-ski shaft stuck
Jet Ski rope wrapped around impeller shaft.

This is something I come across all the time while I am out riding in the river or lake. Many jet-ski owners think that it is ok to ride across a ski rope because they don’t have an exposed propeller. This is completely wrong and can cause major damage to your PWC.

The intake grate on a Jet-ski is designed to ingest large amounts of water at force. This has the ability to suck in a rope as well as other foreign materials. What then happens is the rope begins to get wrapped around the jet pump shaft until it stalls the motor.

A side effect is it can bend the shaft or damage the bottom jet pump hull. So never ever ride across a ski rope in the water or let a rope go slack near the rear of the Jet-Ski.

So how can you remove a rope or seaweed stuck in your intake grate?

Well, the only way is to tow the ski back to shore and put it on the trailer. You can then use a long knife to cut away the rope from around the shaft. If you still can’t reach the rope you will have to remove the three bolts holding the intake grate on. You will then have more room to work in this area. A socket set is best to remove these bolts.

A DIY solution is to use a pool noodle that has been cable tied to the end of the ski rope. This keeps it afloat and away from the pump intake grate.

Seaweed, plastic bags, and rocks will also clog up your intake grate and bring you to a grinding halt.

Jet-Ski wont start

Another common jet-ski problem is that at the beginning of the summer season, a lot of Jet-Skis won’t start. This is usually because of a weak battery. There is just enough voltage in the battery to turn over the PWC, but not enough to provide a large spark to ignite the fuel.
Basically, the battery voltage drops so low that the ignition system will not fire up.

Replace Battery sea-doo procedure
Old Wet Battery to be removed

Top up your battery during the winter months with a smart charger battery tender and then again at the start of the summer season. This will keep your battery at peak charge which will slow down the desulfation process which all wet-cell batteries are prone to. You will have no problems with your battery if you keep it fully charged.

Learning how to desulfate a battery should be high on every car and boat owner’s list of preventative maintenance.

As a backup plan, I like to carry a small lithium-ion battery jump starter for my Sea-Doo. They are light and don’t take up a lot of room. Just wrap it up in plastic to keep the moisture out.

Another problem can be loose battery cable connections. This will cause a problem starting and charging your PWC – Check, clean, and tighten.

Engine misfires, and runs irregularly

Sea-doo gti 130 engine common problems
Sea-doo three cylinder 4-Tec engine
  • Fouled /defective/ worn spark plugs. – Replace. Here is the Sea-doo spark plug replacement procedure.
  • Water inside the sparkplug well, or on the ignition leads. Dry them out.
  • Fuel level too low, old, or water-contaminated. – Siphon out using a fuel pump and refill.
  • Faulty ignition coil – Replace
  • Clogged injectors. – Try using an injector cleaner first and if still clogged replace them.

For more information check out this post if you are having Jetski acceleration problems and solutions.

Hinge broken on Jet ski front storage compartment

Most personal watercraft will have a hinged compartment to store safety gear, fire extinguishers, water bottles, and ski gear. What often happens is people pack so much gear in the front compartment and then slam the lid shut.

Due to the angle of the front hinge, this is often a weak spot, and the hinge or the lid will crack and break. Don’t overload the front compartment and if you do pack it fully close the lid slowly to make sure there is no added pressure on this lid.

The little glove box lid near the handlebars on some Sea-doo can also suffer this same problem. Only pack them 3/4 with gear and you won’t have a problem.

You can repair a broken hinge by purchasing the replacement parts online or trying to fix the plastic hinge with a fiberglass repair kit.

Reverse gate won’t work

sea-doo ibr reverse gate common problems and fixes
Sea-doo IBR forward/reverse drop down gate.

Depending on the brand of Jet-ski some reverse grates will be electrically operated and some will be manually operated with a cable.

Sea-Doo uses an auto-reverse operation system called IBR which stands for intelligent brake reverse. Sometimes the IBR reverse gate can get jammed with a rock or a branch from a tree. Remove the object and try again.

If your forward reverse gate still won’t move you could have a blown power fuse. Replace the fuse and try again.

  • At speeds below 8km/h (5MPH), pulling the iBR lever in will engage reverse.
  • At speeds above 8km/h (5MPH), pulling the iBR lever in will engage the brake.

Yamaha has a manual cable that you pull up, so check for a stuck gate or you could have a broken reverse cable.

Sea-Doo start key is not being recognized.

Sea-doo start key common problem and fixes D.E.S.S
D.E.S.S Start key plugged in.

Sea-Doo uses an intelligent system to recognize that the true owner is riding the jet-ski. Each key is programmed into the memory of the Sea-doo so without this specific key the PWC will not start. Its called the
Digitally Encoded Security System or (D.E.S.S.) Don’t even try to use your friend’s key as this won’t work.

Sometimes when you place the key on the post of the Sea-Doo the craft will not recognize this key. Try to push it on harder as sometimes it could be on an angle.

Also if the DESS post or the key is wet make sure to fully dry them if you are having problems. I have yet to see a Sea-doo start key fail, but occasionally I see people having D.E.S.S key post issues. This key post then needs to be replaced. Saltwater tends to corrode the internals over time.

If you don’t want to go to a dealer and pay hundreds of dollars for a replacement D.E.S.S start key, you can always program on yourself. For this, you will need a Candoo Pro. These can also diagnose common problems on your Sea-doo, Kawasaki, and Yamaha jet-skis.

Check out this full Sea-doo fault code list if you would like to know the details on a specific error code.

Top speed not being achieved

Sometimes your PWC will be slower than normal. Check the intake grate for ropes, rubbish, rocks, and sometimes even large fish which can get caught in the grate. If the inlet grate is all clear then check to see if you are using a learner key as this will restrict the RPM as well as the top speed. Another problem could be that the speed mode could have been changed from sports/normal to ECO mode.

A worn-wear ring or impeller can also cause cavitation and reduced top-end speed. Be sure to replace these if this is the cause. Finally, check the forward-reverse gate is fully in the upright position.

If all else fails your Jet-Ski could be in limp mode due to an engine sensor problem. An overheating Jet-Ski will also put you into limp mode. You will have to take your PWC to a dealer to diagnose the exact problem.

Jet-Ski filling with water

Jet-ski water leak from cooling system drain water

Firstly you need to work out if your jet-ski is filling with water when running or if stationary sitting in the water.

If it is filling with water while stationary then take off the seat and use a torch to see where the water is flowing into. Often it is a bad seal on the main shaft or there is a compression fitting on a hose that is loose and will need tightening. Or somebody forgot to put the drain bungs back in.

Under running conditions, it’s a lot harder to check for a water leak. The easy way is to keep the PWC on its trailer and put it in the water. You need to reverse the whole trailer into the water until the bottom of the jet ski intake grate is underwater. Leave the seat off and start up the Jet-ski. Look to see where the water is coming in. Often it will be from the pump seal or the cooling circuit.

I have a bilge pump in the hull of my Sea-doo. It is automatic and will start up once water is detected in the bottom of the hull.

Here is how I installed a bilge pump in a Sea-doo jetski.

Never use a PWC with a water leak as it could increase rapidly and fill your entire hull with water. If this happens your craft will begin to sink and the motor will fill with water. The Sea-doo RPX shown below was saved by getting towed back to the boat ramp.

Spark plugs hard to remove

If a Jet-ski has not been serviced in a few years it may be hard to remove the spark plugs. This is because rust can cause the plugs to bind to the engine head. Use some penetrating fluid and leave overnight.

Try and remove the plugs again using the correct socket and a long extension bar. If the spark plug breaks you can remove the plug with an easy-out extraction tool. Be sure to check inside the piston with a camera to make sure no loose particles fell inside.

On replacing the spark plugs use a small amount of never seize to make them easy to remove next time. Torque them up to the correct specifications of the spark plug. Seized spark plugs are a common Jet Ski problem due to the environment they are used in.

Mold and Mildew on the seat and inside the engine bay.

mold on inside of jet-ski hull
Mold inside a Yamaha FX Engine bay

If you don’t let your Sea-Doo, Yamaha, or Kawasaki Jet-Ski air out after each use you will start to attract mold on your fabric and inside your engine bay.

This mold fungus is hard to remove unless you use a bathroom mold remover. Just spray it on and let it go to work. Make sure to rinse the area with fresh water after treatment.

clean mold from inside of jet-ski hull using anti-mold solution.
The difference in the fuel tank straps after mold removal treatment.

One way to guarantee that the mold and mildew doesn’t return is to remove your PWC seat and drain any water inside the watercraft. I even go as far as to sponge out any remaining water that may pool in hard-to-reach areas.


Hopefully, some of these common jet-ski problems and repair tips will help you in getting your PWC back into the water fast. 9 times out of 10 it is a simple fix that you can do yourself.

If you are looking to purchase your first PWC or looking to buy another then check out our article on what to look for when buying a used Jet-Ski. It’s full of technical checks for you to do to make sure you don’t buy a lemon.

Having the correct tools on hand will make the job easy. You don’t need to bring the whole workshop with you. But every watercraft should at least have the basic tools that I mentioned at the beginning of this article.

Ride safe and let me know in the comments below what problems you have with your Jet-ski and how you have fixed it yourself.

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  1. My parents really want to get a jet ski this fall. It is good to know that they should look out for mold growing on the tubes in the engine. I wouldn’t have thought about how that could be possible.


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