How to Repair Kawasaki JS440 Jet Skis


Kawasaki released the JS440 jet ski in 1977, only four years after the company first began manufacturing personal watercraft. An upgrade from the company's popular JS400 make of jet ski, the JS440 offered more power and speed to riders. This model lasted until 1992 and became Kawasaki's longest running jet ski. For minor repairs and troubleshooting, Kawasaki offers instructions in the JS440 owner's manual, though Kawasaki recommends that only certified dealers attempt serious repairs.

Things You'll Need

  • 12-volt, 19 ampere-hour battery
  • Damp cloth
  • Wrench
  • Spark plug wrench
  • Spark plug gap tool
  • NGK BR7ES spark plugs
  • Unleaded gasoline
  • Coolant

Engine Doesn't Turn Over

  • Verify that the starter interlock switch, located on the left handlebar near the driver's thumb, is positioned to the right if the engine will not turn over. The engine will not start if the switch is positioned to the right.

  • Remove the battery if the engine still won't turn over. Disconnect the black lead from the battery first then the red lead with a wrench. Release the rubber straps and lift the battery out of the JS440's hull.

  • Inspect the battery connections. Clean them with a damp cloth if they are dirty and tighten them with a wrench if they are loose.

  • Charge the battery to 12 volts by connecting it to a separately-powered charger. Set the charge rate to 1.9 amps and charge the battery for 12 hours. Reinstall the battery.

  • Try the engine again. If it still won't turn over or turns over slowly, take the JS440 to the shop for inspection.

Engine Misfires or Stalls

  • Check the fuel levels first if the engine misfires or stalls. If the tank is empty, refill it with unleaded gasoline and restart the engine.

  • Restart the engine, if the rider may have used the choke during operation, as this can cause the engine to misfire. Only use the choke while starting the JS440.

  • Remove the spark plugs with a spark plug wrench and inspect them. Make sure that they are NGK BR7ES spark plugs as recommended by Kawasaki.

  • Replace the spark plugs if they are cracked or black in color.

  • Set the spark plug gap for each plug between 0.028- and 0.032-inch. To shorten the gap, press the hooked end of the spark plug against a firm, hard surface until it is between these measurements. To elongate the gap, insert a spark plug gap tool into the space between the hook and gently bend it out to the correct measurement.

  • Restart the engine again. If the engine continues to misfire or stall, take the JS440 to a Kawasaki dealer.

Engine Overheats

  • Inspect the jet pump at the back of the JS440 for debris or seaweed. If debris is present, turn off the jet ski and remove any visible debris.

  • Check the coolant levels once the engine has cooled fully. Open the radiator cap and check the coolant levels in the reservoir. If the coolant levels are low, refill the reservoir with fresh coolant. If there is visible leakage around the radiator or coolant lines, take the JS440 to a Kawasaki dealer for repairs.

  • Verify that the fuel tank contains unleaded gasoline only. If you suspect that an incorrect fuel has been used, take the jet ski to the shop to drain the fuel tank. Refill it with unleaded gasoline.

Tips & Warnings

  • Both batteries and gasoline give off explosive fumes. Do not smoke or work near an open flame while inspecting these systems.
  • Always wear goggles and gloves, when handling batteries, to avoid burns from battery acid.

Related Searches


  • Photo Credit jet ski, image by razorconcept from
Promoted By Zergnet


You May Also Like

Related Searches

Check It Out

How To Travel For Free With Reward Points

Is DIY in your DNA? Become part of our maker community.
Submit Your Work!