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Reasons Why Your Jet Ski Won’t Start

It can be very frustrating when you go out to hop on your Jet Ski and find out that it won’t start. I’ve created a list of the most common reasons why your Jet Ski won’t start and what you can do to fix the issue.

WARNING! Batteries and the starting system of your jet ski carry HIGH ELECTRICAL CURRENTS, which can hurt or seriously harm you if you don’t know what you’re doing. If you don’t know what you’re doing, please have your local dealer look at it for you.

Dead Battery

Random jet ski batteries that are dead

Having a Dead Battery is usually the biggest reason why your Seadoo, Yamaha, or Kawasaki jet ski won’t start.

8 out 10 times, it’s the battery. Even if you charged the battery or it’s a new battery, it still can be the battery causing the jet ski to not start. Even if you think the battery is good, check the battery. We talk more below about how to check the battery. 

  • If you put the key on and nothing happens then, the battery is completely shot and needs to be replaced.
  • If you put the key on and the display turns on, but when you press the start button, and all you hear is clicking that means the battery is weak. A weak battery will need to be charged.

You may also like this post: REASONS WHY YOUR JET SKI BATTERY DIES

To charge a battery, you want to use a smart battery charger (Amazon Link Ad) that does not exceed 2 amps. Also, you need to let the battery charge for hours, or overnight to get it to be fully charged. To keep the battery from dying all the time I highly suggest getting a Solar panel like this one (Amazon Link Ad). Just hang the solar panel off to the side when you’re not using the jet ski.

Sometimes you’ll need a new battery (Amazon Link Ad). Your local dealer can help you find the correct battery for your machine.

One Solid Click or Thud

If you go to start your watercraft and all you get is ONE solid click or thud, then the Starter Relay (Amazon Link Ad) has gone bad. Also, you know the starter relay is bad is when you press the start button multiple times before the jet ski will finally start.

I have even had customers tell me the procedure to start their watercraft, like waiting for the dash to turn off, then you press the start button 11 times while tapping the handlebars 4 times before it will start. There is no special procedure for starting a jet ski, and if you have to do something very similar, you need a new starter relay.

The starter relay is the device that sends the power from the battery to the starter motor to turn the engine on. The way you determine if the starter relay is bad or if the battery is bad is by the clicks. A bad battery will cause the starter relay to make multiple quick clicks, while a bad relay will do only one click when you press the start button.

Your local dealer will more than likely have Starter Relays in stock. For some model Jet Ski’s, I highly recommend letting the dealer install them as some can be very painful to install. It’s only a couple of wires, but the location of the relay can be very difficult to get to, and having the dealer do it could be worth it.

Battery and Starter Relay are Fine, now what?

If the battery and starter relay seems fine and has passed all test above then, I would check the battery again. There have been plenty of times where the battery charger says the battery is charged and ready to go, but when I put a load tester on the battery, it was a different story.

I would even take the battery to your local dealer or even an auto parts store to have them load test the battery to make sure it’s okay.

If the battery passed the load test, the gauges come on, and the starter relay is good or has been replaced, then you only have a few more options left. The next thing in line is the Starter, and it could have gone bad. It’s not common for the Starter to fail, but the starter relay and battery will fail eventually because of the stress they go through (they’re wear-and-tear items).

If you have gotten to this point, you’ll need to take it to your local dealer. If the problems are beyond the battery and starter relay, then something is going on beyond your control. Your local dealer can hook the machine up to the computer to see what is going on and what needs to be fixed.

Sucked Something Up

It’s rare, but one reason why your jet ski won’t start could be due to you sucking something up. A stick, rock, or even rope can get in there and wedge itself in keeping the pump and also the engine from spinning over.

I go into more detail about this here. Usually, when you suck something up, you notice it, but maybe a friend returns the machine and doesn’t tell you about it, and this would lead you to this conclusion.

Sum Up Jet Ski Won’t Start

  • Why your jet ski won’t start can be a bad or weak battery, bad starter relay, bad starter motor, or you sucked something up.
  • 8/10 times a jet ski won’t start is due to a weak battery or bad starter relay.
  • In rare occasions, the key or other electronic parts could be the reason why your jet ski won’t start.
  • If your jet ski clicks once when you hit the start button then it’s more than likely the starter relay.
  • If you have to press the start button multiple times or put the key on and off before the jet ski starts then it’s a bad starter relay.
  • If your jet ski clicks multiple times when you hit the start button then it’s a weak or dead battery.
  • If you’ve put a new battery in your jet ski and it still won’t start then it could be that the new battery is dead and needs to be load tested.
  • Never go off on what a voltmeter says but instead what a load tester says when checking if a battery is good or not. You can get load testers at many stores but most auto parts stores will have a load tester you can use for free.
  • If your new battery load test fine and the watercraft still won’t start then it could be bad grounds or other electrical issues.

201 thoughts on “Reasons Why Your Jet Ski Won’t Start”

  1. Howdy!
    I’m vacationing in the Florida Keys with our twin 2020 GTX Limited. We have been using them without issue but left them in the water well secured this week. No bouncing around or hitting anything, but did have heavy wind. We went to use them today and both are not starting. Key registers, dash comes on, but continuously turns over. Any ideas how we can troubleshoot? We already had the batteries replaced about 6 months ago, and both are well charged.

    Reply
    • This doesn’t sound like a battery or starter relay issue as it turns over. It sounds like a spark plug or ignition problem. It could also be a bad gas problem too.

      Reply
  2. HI Steven, our 2001 Sea Doo GTI stopped running last week. First time we had it out this year. My son thought it was a Low Oil Pressure Shutoff to protect the engine. Cannot find anything listed saying this is a feature. I did fill the oil & the engine turns over great, but will not fire. If the Starter relay was bad, would the engine turn over? Any other helpful hints to check?

    Reply
    • If the engine turns over the starter relay is fine. Since it’s a 2-stroke I would start by replacing the spark plugs first.

      Reply
  3. I have a 2007 and 2008 Seadoo GTI 155. Both have similar hours right around 70. So after storing them for winter this year we were going to take them out a few weeks ago. We had the batteries stored in our basement on a shelf. Put them in and went to fire them up. The 2008 fired right up and was ready to go. But the 2007 when putting the key on the DESS post the screen came on for a short period, but there were no beeps at all. Then I tried starting it thinking maybe the beeper wasn’t working. Nothing at all. So I switched the battery out of the one that was working thinking maybe it was just the battery. Again the same exact thing. So it wasn’t the battery. Did some research and wasn’t really a whole lot about the topic on that model year. I found some stuff that suggested that it was possibly the DESS post was bad and I would need a new one. So I wired up the new DESS post. Same exact thing. When the key is put on you can here like a pump is turned on or something and the screen comes on for like 5 seconds and then goes off. Nothing else comes of it. I put my key from the 2008 on it to see what it would do and it has the same result as what happens with the correct key.

    Any ideas would be much appreciated thanks!!

    Reply
      • So would the best bet be taking it to a dealership and seeing what computer system has gone bad? Because the computer systems are very expensive? or is there a way to diagnose it by my self.

        Reply
        • The best thing you can do is take it to the repair shop and let them hook it up to BUDs to see what is wrong. It could be something simple like a terminal is loose or as bad as the ECM is bad.

          Reply
  4. I have a 2001 xlt 1200 yamaha waverunner. When i hit the start button it makes a lound horn like sound and i can feel vibration under the black yamaha cover. Any idea what it could be, sounds like starter isn’t engaging but not sure. have a video of it on my phone

    Reply
    • That’s a new one, I never heard a jet ski make a horn-like sound. The thing that comes to mind is the starter motor jammed or something in the pump is jammed.

      Reply
  5. Hello Steve

    I have a 2008 Kawasaki 15F and my frustration is that when the ski is cold it starts right up, runs a little ruff until it warms up then runs great. When i come back in and try to restart the ski it will not start until it cools down? I have changed the battery, I also change the plugs every year. Last year i even change both coils because i thought maybe they went back. I would appreciate any advise.

    Reply
    • I would check the fuel injectors. I had a jet ski that did something very similar to this and it was because of the fuel injectors and bad gas.

      Reply
  6. Hi Steve, I’ve got a Yamaha vxr 2012. Battery had plenty of charge but when we tried to start it there was a faint electrical buzz but did not try to kick over at all. Tried pressing the start button multiple times but same thing happened. It eventually kicked and started. I switched it off after about 5 minutes out on the water for about 2min then tried starting it again and it wouldn’t start. Took the seat off and wiggles the cords and it eventually started again. It ran fine for another 2hrs then after we got it out of the water to clean it out with fresh water it wouldn’t start again. Checked the battery and it was still fine… is that likely the start relay or another electrical issue?

    Reply
  7. Hi Steven, we bought a 2005 seadoo Gtx 155 last summer. Had a blast at the lake all year. We got it winterized end of the season, and it’s been stored in the garage. We are taking it back to the lake next week. What do u recommend for maintenance each year? Should I go ahead and get the oil changed and new spark plugs each season before I take it out? And is winterizing at my dealer all I need to do at the end of each summer? Thanks!

    Reply
    • What I do is get my jet ski winterized with oil change every year, I only do this because things are cheaper in the winter and I don’t need it then. Then when the season starts I put some fresh gas in the tank and change the spark plugs. If you didn’t have the battery on charge during the winter I charge the battery or get a new one. If you didn’t change the oil in the winter I would go ahead and do it before you ride. An oil change once a year and new spark plugs every year is a must and if it gets below freezing where you live you need to winterize it every year too.

      Reply
      • Thank you. They winterized it, but did not change the oil, so I will do that now. Also we are going to get the solar charger you recommended because we did not put it on charge all winter. Hopefully it will not be dead for good. It was a new battery last year. The solar charger u recommend comes with a cigarette lighter plug… I assume u don’t use that? And just hook it up to the battery and hang the solar panel off? Also, heard conflicting things about getting it winterized. We filed the gas tank with new gas BEFORE winterizing it. When I too it to the dealer, he said I SHOULDNT have filled the tank, and instead left it pretty low.. your suggestion? Is my full tank going to need to be siphoned out now? 🙁

        Reply
        • You connect the 5-watt solar charger directly to the battery. These solar chargers often come with clips that you connect to the terminals of the battery. Leave the solar panel somewhere that the sun can get to it. If the battery is already dead the solar charger might not charge it up enough, it’s more to maintain the battery. You’ll need to get a 12-volt smart charger rated below 2 amps if the jet ski won’t start or the battery is weak. If the smart charger doesn’t charge the battery then you’ll need a new battery. I leave all my jet skis with 1/4 of gas for the winter, never fill it up and let it sit. Gas goes bad over time. Then when the season starts I fill the tank with fresh gas. If you stored the gas without STA-BIL in the tank the gas might not be good. The high-HP jet skis can get picky about their gas, if it’s slightly bad check engine lights go off. I would have the dealer check the gas and if it need be taken it out.

          Reply
          • Thanks for the quick replies! Ok, last questions.. if we store the seadoo in a garage all winter, it wouldn’t get any sun, so how often should we hook it up to the smart charger in the winter, and how long to leave it on each time? When they winterized it, they did put stabil in the gas, so perhaps it will be ok? Would stink to lose a whole tank of gas. And finally, is the starter relay an expensive fix? Ours may be going bad bc we have to push it a few times sometimes for the engine to fully turn over. We have noticed the DEES key has to be put on the post just right also.

          • In your case, I would take the batteries out of the jet ski and put them somewhere off the ground in your garage. Then a few days before you get you jet skis ready for the season charge the batteries with a smart charger. If you got STA-BIL in the gas when it was winterized you should be fine. Replacing the starter relay can easy on some models and hard on others. From what you describe it sounds like you need a new starter relay. Just make sure the battery is disconnected and out of the jet ski before you replace it. This is for safety and often it’s so much easier to replace the starter relay with the battery out of the way.

  8. Hi Steven, great article! So…. here’s my situation… 1997 Seadoo GTI. Bought it a few weeks ago, all service performed by local mechanic. Local mechanic gave advice to crank it up out of water and warm it up prior to placing it in the water after I called him and advised him it wouldn’t crank in the water. I took his advice and it ran for a while; however, it just completely shut off on me a few times while riding as if I detached the cap key from the Seadoo. I checked the key but it was still attached. I held the start/stop button down for a moment several times without it doing anything and it finally cranked back up and made it back to the dock. Later, I checked to see if the Seadoo would crank while on the trailer and now there is no beep when I place the key on, the gas gauge turns on and the red light turns on quickly and both go off. During that quick moment I am pressing the start/ stop button but there is no clicking or anything in the engine. I checked ALL fuses, I checked the battery voltage and am good on that. I placed a screwdriver across the starter relay solenoid bolts without the key on the Seadoo and it sparked and sounded like it was going to crank. Starter Solenoid relay ? If it is the Starter Solenoid Relay would that also have an affect on the beeper? Thanks for your help!

    Reply
    • I’ve seen the start buttons on those models go bad or the key or DESS post. It sounds more like the DESS or Key is bad but a 23-year-old jet ski is bound to have a handful of problems so fixing the start button would be worth it too.

      Reply
  9. Hi Steven, 
    I read your article it’s great. Thank you for all of your advice here. 
    I made a post yesterday here; however, I’m not able to see it. That is why I am writing this post for the second time. 
    I bought the Seadoo Spark 2014 last year around August with a bit broken(cracked) hull that I fixed without any problems. 
    When I bought the jet ski I tried to turn on the engine; however, I was not able to start the engine and I thought that probably the battery is weak or I need to replace the spark plugs. ( I heard the sound that engine is trying to start)
    Now when I have a bit more time I try to turn on the engine; however, I’m not able to and I don’t hear anything except one click. 
    I replaced the starter relay. 
    I replaced the starter solenoid 
    I’ve checked the battery and it is good( I’ve checked the battery for load in Auto Zone)
    I’ve checked the starter (It’s working great)
    I’ve also checked all of the cables from battery to starter solenoid and from the starter solenoid to the starter. 
    All of the fuses are good. 
    When I replaced the spark plugs I noticed that they are rusty, and that rust is on the top of the pistons. I wonder if it is possible that pistons got stuck?
    What is your opinion on what can cause that engine this problem?

    I didn’t winterize the engine because I have no idea that I should do this. I don’t know if this is important, but I live in a place where winter is warm and I parked Jet Ski in the garage all the time. 

    Could you please give me any suggestions on what I can check before I will go to the dealer?

    Thank you!

    Reply
    • A hole in the bottom of the jet ski and rust in the cylinders is not a good thing. It sounds like the Spark sunk and the engine took on water and made it hydrolocked. This is not a good sign, I suggest taking it to the nearest repair shop.

      Reply
      • The hull was broken outside the water. The engine is completely clean and looks like new and the hull inside looks like new is very clean. I don’t see any signs of water inside the hull, so I do believe that the damage was done outside the water. 

        Reply
        • Something is not right as spark plugs should not rust. The person who sold you it could have cleaned it up. Something is not right and will need a repair shop to tear apart the engine to see what is going on.

          Reply
  10. Hey – 2006 STX 15F owner – bought it used and it ran great for 3 hours
    3rd trip out it will crank hard but not start
    Smart trickle charged the battery and it was at 13v
    Check that fuel was geting to the rail
    Engine cranks hard but never fires

    ideas?

    Reply
  11. Ok, so my 91 Kawasaki TS has a very similar issue! When you go to start it and all it does it click, keep holding the start button. I did this for roughly 10 seconds and when i hit the starter button again, it actually turned the motor over. I know, weird….but try that and let me know how that goes.

    Reply
    • Sounds like you need either a new battery or a starter relay. If it’s multiple clicks you need a new battery, one single click then you need a new starter relay.

      Reply
  12. Hello Dear,

    I have Yamaha Ex model Jetski. It unable to start, so after charging it got dry start. But in water it unable to start again. It happens twice the same. So I changed battery to 12v 18 amh (as 19 amh not available in market). Now engine not starting, only there’s tick sounds. Voltage showing greater than 12. What could be the reason please. Is there anything serious.

    Reply
    • Sounds like you need a new battery, the one you have has gone bad. Even if the battery charger says it charges fine it still sounds like you need a new battery.

      Reply
  13. Hi Steven!

    I have a 2004 Seadoo GTX 155 4tec 160hour.
    When the engine is cold starts fine (on the trailer and also in the water).
    After riding when the engine is warm it takes a lot of cranking to get it started.
    Does my starter stop cranking (slow) after a few seconds (like it’s a feature to save the battery), then I have to press start again and go through this 3-4 times before it fires up. Once it starts it runs fine, and always starts right up when cold. Thank’s! Leslie

    Reply
    • This is a super odd one. It’s either fuel or a compression problem. This is one of the times I’ll say you need to take it in so someone can get their hands on it and figure it out. I’ve never run into this problem before.

      Reply
  14. Have a 2011 yamaha vxr. Started up once (no problem), let it ran for 15 seconds, started up twice (no problem), ran 15 seconds, then 3rd time it clicked and the green security light came on, it didn’t start. I let it rest for 30 minutes and it just the green security light came on.

    Reply
  15. Hi Steve, i have a 1991 Kawasaki 650TS and am having starting issues. I replaced the battery, starter solenoid and starter with no change!?!?!! When i hit the starter button it cranks super slow for a few seconds then all i hear is the solenoid clicking. I can start it with a battery charger on 10 amps and after its warm it will start back up almost every time!! Also getting over 12.4v when it runs, can you suggest anything else to try?

    Reply
    • If you can start it with the extra help of the battery charger then that tells me the battery is not good even if it’s new. The battery charger is supplying enough power to make up for the weak battery and that is why it’s starting. Also, if it’s only at 12.4 volts when running it tells me the rectifier or something in your charging system is not working. It should be hovering higher between 13.5 to 14.5 volts. Also, don’t forget to clean the connecting battery wires as they often develop corrosion over time. When you do get another battery make sure to charge it completely with a smart battery charger.

      Reply
  16. Hey steve,
    I’m 16 years old and my grandfather owns a 1999 Seadoo gtx he’s no longer physically able to A) ride and B) work on it. Me just getting my boating license have now decided to turn this into my little project to fix it up, so here’s my problem, I put the key on and only 50% of the time the dash board comes on, and when it does it and I go to start it, it gives a kick and dies out, we tried charging the battery and that didn’t seem help. When we do get it to start it dies when you don’t touch the throttle and you have to take the key out and try again. Do you think I need a new battery? Or could this be something else. Thx in advance

    Reply
  17. Hi Steve
    I njhave a 2005 GTX DI and it was running great. then my son took it out 15 minutes after I had just gone for a ride and it suddenly quit on him. We can start it but now it dies within 5 seconds in idle and quits immediately when moving the throttle. I replaced the spark plugs and checked all electrical connections but no luck. could it be a fuel pump or filter? looks like a monster job to get t out if it is

    Reply
    • Honestly, it could be many things with those DI’s. The DI’s from my experiences always get some type of phantom issue that makes it act odd. The fuel delivery system sounds like your issue and it could be the fuel pump or fuel rails. It’s hard to tell on DI’s but fuel seems to be your issue. It would be best to take it to a repair shop especially one that deals with 2-strokes. Those DI’s are cursed if you ask me.

      Reply
  18. Thanks. Based upon my experience with solenoids and the few PWC local technicians comments, I did not bypass the solenoid during the initial troubleshooting. No traditional clicking sounds, just the whirring noise noted in the earlier post. The whirring noise happens at the initial safety key is inserted on the dash for three or four seconds and then stops and then happens again when the start button is pushed. Just to be sure I decided nothing hurt through bypassing the solenoid and did so and the jet ski turned over fine – starter appears to be okay with that. Is the solenoid the most likely problem or is it possible that there is an issue with the MPEM? Can the MPEM cause the solenoid not to engage? I’m not getting a clicking sound when depressing the starter, only the whirring sound like a small electric or hydraulic motor spinning. It will do so as long as the starter button is depressed. I’m glad to replace the solenoid, cost is low, but I’m stumped by the whirring sound and wonder if there is a problem ahead of the solenoid. I have been unable to find this specific issue in talking with three technicians and looking at on-line postings. Many refer to the clicking of a solenoid as an indicator (which I don’t have happening) but no one has heard of a whirring sound happening under any condition. Any additional thoughts?

    Thanks again for the first response.

    Reply
    • That sound was common in some DI models and early 4-tec engines. It’s the fuel pump and other compoents “priming”. Every time you put the key on or press the start button you’ll hear this humming like sound. I would replace the starter solenoid and then go from there. Make sure the battery is not connected when you replace it.

      Reply
  19. Hi Steven,

    Thanks for your very useful comments on jetski starting. I hop you are able to provide possible direction or confirmation on the issue below.

    2000 Seadoo RXDI

    1. Won’t start. Battery depleted.
    2. New battery installed.
    3. With safety key inserted two short beeps occur. Electrical panel displays with status information.
    4. The first time inserting the safety key with the new battery the double beeps occurred and then there immediately follow a long beep. This happened twice. I couldn’t find a reason for the long beep of which several are listed (wrong lanyard, defective lanyard, safety lanyard in too long without starting or bad MPEM.
    5. An attempt was made a few minutes later and there was no long beep following the initial two short beeps.
    6. With the two beeps and no following long beep, the red start button was pushed and there was a humming sound similar to what a spinning electric motor or the sound a small hydraulic motor might make. Nothing else happened. No clicks or other sounds like I am familiar with on automotive units when a solenoid or battery is weak or bad.
    7. At the next attempt the humming sounded as soon as the double beep was heard with the insertion of the safety key, but without depressing the start button.
    8. The humming sound continued on its own for a few seconds and then stopped.
    9. The red start button was pushed and the humming sound initiated again until the red button was released. The start button checked to verify it was not stuck/sticking in a depressed position. It was not.
    10. Time was taken again to verify battery electrical connections were tight, which they were.
    11. The electrical box opened. What to me seemed a significant amount of water found inside. Water removed and the unit dried out, connections of all location checked and the attempt to start the unit again made with the same result as noted above, i.e. motor hum sounded as soon as the safety key was inserted, then stopped on its own and when the start button pushed the only sound was again the same hum as long as the red button is depressed.

    Despite being a 2000 model it has only 107 hours on it.

    Bad starter motor? Bendix not engaging? Other things I can check? I am told replacement of the starter motor is difficult and expensive due to time.

    Thanks for any thoughts or direction. We don’t have a local dealer or repair so I would appreciate as much direction as possible before traveling to a dealer.

    Jack H.

    Reply
    • I would start with the starter relay and then the starter motor. The starter motor won’t be easy but nothing is easy on any DI models. The honest truth is that any DI Sea-Doo I’ve run into always had some type of phantom electrical problem. You’ll fix one thing but another electrical problem will show up soon. Hopefully its something simple like the starter relay.

      Reply
  20. Hi Steven
    Have 1997 STX1100. When I hit the start button, I can here the starter turning but the engine does not turn over. Replaced battery with new one and a new solenoid. What could be the issue. Thanks Pat

    Reply

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