How to Troubleshoot a Yamaha Jet Ski

by Brianna Collins
spark-plug wrench image by Aleksandr Ugorenkov from

Besides its extensive lineup of land-based recreational vehicles, Yamaha has also been steadily building its selection of jet-ski models. Yamaha offered a dozen different models in the Wave Runner line in late 2010 alone, ranging in design from sporty single Waverunners to cruising models capable of handling multiple riders. Despite this variety in different Waverunner models, Yamaha offers similar troubleshooting tips for all of its jet skis.

Engine Doesn't Start or Turn Over

Step 1

Unselect "Lock Mode" in the Yamaha Security System.

Step 2

Check the engine shut-off switch. If its clip is not in place, install it correctly and restart the engine.

Step 3

Check the battery. Tighten all connections and recharge it. If the battery or connections look damaged, replace them and try the starter again. If it still will not start, proceed to the next step.

Inspect the starter motor. If it appears damaged or faulty, take the Waverunner to a Yamaha dealer for inspection.

Engine Doesn't Start but Turns Over

Step 1

Make sure you are not trying to start the Waverunner with the throttle lever squeezed by your right hand, as the engine cannot start with this lever depressed. Release your grip and start the engine.

Step 2

Check the gas tank for fuel. If the tank is empty, refill it with unleaded gasoline. If adequate gasoline levels are present, inspect condition of fuel in the tank. If it looks watery or gummy, it may be contaminated or stale. Bring the watercraft to a Yamaha dealer to flush and refill it.

Step 3

Remove the spark plug and inspect it and the electrode. If the electrode is dark brown or black, the spark plug may be damaged. Replace it and check to be sure that you have set the spark plug gap to the specifications in the owner's manual of that particular Waverunner.

Restart the engine. If it still won't work, take the Waverunner to the shop, as this may indicate a problem with the fuel pump or fuel system.

Engine Stalls or Misfires

Step 1

Check that there is enough fuel in the gas tank and refill it as necessary.

Step 2

Check for water or dirt in the gas tank. If debris is present, take the Waverunner to a Yamaha dealer.

Step 3

Set the spark plug gap correctly and replace the plug(s) if they are damaged.

Step 4

Have a Yamaha dealer inspect the Waverunner if the spark plug cap is damaged or not connected.

Inspect the electrical system for loose connections and take the jet ski to the shop for tightening if loose connections exist.

Warning Light/Indicator Blinker is On

Step 1

Check the fuel tank and refill if necessary.

Step 2

Take the watercraft to the shop if the oil pressure warning comes on.

Step 3

Look inside the jet intake. Remove any seaweed or other debris that may have become lodged in the intake, taking care not to damage the intake itself. A clogged intake can cause the warning light to come on and make the engine overheat.

Take the Waverunner in for inspection if you suspect faulty warning sensors.


  • Take the Waverunner to a certified dealer if troubleshooting fails.


  • Gasoline emits explosive fumes. Do not smoke or go near heat while handling fuel.

Items you will need

  • Gasoline (unleaded)
  • Spark plug wrench
  • Spark plug(s)
  • Battery

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