How to Get Your Jet Ski Ready for Summer (Pre-Season Checklist)

The water's warm, the trailer is hitched, and you're ready for the first ride of the season. Before you back down that ramp, take 15–20 minutes to run through this checklist. Most season-opening breakdowns are caused by something that would have been obvious on a quick inspection at home. Find it in the driveway, not two miles from the dock.

This checklist applies to all major PWC brands — Sea-Doo, Yamaha WaveRunner, and Kawasaki Jet Ski.

If You Properly Winterized: What to Check

If you followed a proper winterization procedure last fall, most of your ski is already in good shape. Your spring prep is lighter — mainly reinstalling the battery, a fluid check, and a pump inspection. Here's the full rundown either way.

Pre-Season Checklist

1. Reinstall and Test the Battery

If you removed the battery for winter storage (as you should have), reinstall it now. Check the terminal connections — they should be clean and tight with no corrosion. If you used a battery tender over winter, the battery should be at full charge. If not, charge it fully before the first start.

A healthy jet ski battery should show 12.6–12.8 volts at rest with a multimeter. Anything below 12.4 volts on a rested battery suggests it's holding less capacity than it should. If the battery is 3+ years old and isn't holding a proper charge, replace it before the season starts rather than getting stranded on the water.

2. Change the Oil and Filter

If you changed the oil before storage (correct procedure), you're fine — just check the level and confirm there's no milky discoloration that would indicate water intrusion over winter. If you didn't change it before storage, do it now. Fresh oil at the start of the season is cheap insurance.

Check the oil level with the ski on a level surface. On most 4-stroke Sea-Doos and Yamahas, the dipstick is accessible from the front storage area or engine bay. Oil should be at the full mark, clean, and amber-colored. If it looks brown-black or milky, address that before riding.

3. Inspect the Fuel System

If you added fuel stabilizer last fall and filled the tank, the fuel should still be good. Smell the tank — if fuel smells sour or varnish-like rather than like fresh gasoline, it's degraded and should be drained and replaced before starting. Old ethanol-blended fuel can gum up injectors quickly.

Check the fuel lines visually for cracks, especially near the fittings. Rubber fuel lines can harden and crack over a cold winter. A cracked fuel line in the engine bay is a fire risk. Replace any line that shows surface cracking or stiffness.

4. Inspect the Jet Pump

This takes 5 minutes and can save your day. With the ski on the trailer:

• Hand-spin the impeller through the pump nozzle — it should turn smoothly and quietly. Any roughness, grinding, or resistance indicates bearing wear.
• Check the impeller blades for chips, bends, or erosion. Even small chips cause vibration and reduce efficiency.
• Run your finger inside the wear ring — should feel perfectly smooth. Grooves or scoring means it's due for replacement.
• Check the intake grate from below — should be clear, undamaged, and all fasteners tight.
• Inspect the zinc anode — if it's more than half consumed, replace it before launching. It's your pump's protection against galvanic corrosion.

5. Check the Spark Plugs

Spark plugs are one of the most overlooked maintenance items on a jet ski. They're inexpensive, easy to replace, and a fouled or worn plug causes hard starting, rough running, and power loss. Pull them and inspect:

• Light tan or gray color = healthy combustion, plug is fine
• Black and sooty = rich running or fouling, may indicate a fuel issue
• White or blistered = lean running or overheating, needs investigation
• Worn electrode (rounded, not sharp) = replace regardless of color

If your plugs haven't been changed in two seasons, just replace them now. A set of spark plugs costs $15–25 and a fresh set makes a noticeable difference in starting and throttle response.

6. Inspect Hoses, Belts, and Clamps

Open the engine bay and do a visual sweep:

• Coolant hoses: look for cracks, swelling, or soft spots. Squeeze them — they should feel firm and pliable, not hard and brittle.
• Hose clamps: all should be tight. A loose clamp on a cooling hose can cause sudden overheating.
• On supercharged models (Sea-Doo 230/300 hp, Yamaha SVHO): inspect the supercharger inlet hoses for cracks. These are under boost pressure and a failure at speed can be immediate and catastrophic.

7. Test the Safety Systems

Before you ride, confirm all safety systems are functional:

• DESS / safety lanyard: Attach the lanyard, start the engine, then remove the lanyard. Engine should stop immediately. If it doesn't, the safety cutoff is not working — do not ride until it's fixed.
• iBR (Sea-Doo models): Test the braking function at low speed in a safe area before heading out. The iBR system sometimes needs a moment to calibrate after sitting.
• Throttle response: With the ski on the trailer (engine off), move the handlebars through full lock-to-lock. Confirm no binding, and confirm the throttle cable moves smoothly through the full range.

8. Check the Hull and Drain Plug

Inspect the hull for any cracks that appeared over winter — pay attention to the area around the intake grate, pump tunnel, and bow. Small gelcoat cracks are cosmetic; cracks that go through the hull material need repair before launching.

Do not forget the drain plug. This sounds obvious, but a missing or improperly seated drain plug has ended countless first rides of the season. The plug should be installed hand-tight plus a firm turn, and it should have a fresh o-ring or washer if the old one shows any deformation or hardening.

9. Check the Fire Extinguisher and Safety Gear

PWC safety equipment gets ignored until it's needed. Before the season:

• Check that your fire extinguisher (if stored with the ski) is still within its service date and the gauge reads in the green
• Inspect life jackets for tears, broken buckles, or hardened foam that no longer springs back
• Make sure your registration is current and displayed correctly

10. Do a Wet Test Before Your First Full Ride

If possible, do your first start of the season in a controlled setting with the ski on a flush adapter rather than in the water. Run it at idle for a few minutes and confirm there are no unusual noises, warning lights, or fault codes before loading it up and heading to the lake. If anything flags, you'd rather deal with it at home than at the ramp.

First Ride of the Season: Take It Easy for the First 10 Minutes

Even if everything checks out, let the engine warm up fully before going wide open. Cold oil doesn't circulate as effectively and tolerances are slightly tighter until the engine reaches operating temperature. Cruise at moderate speed for the first 5–10 minutes, confirm everything feels right, then enjoy the season.

Parts That Are Commonly Needed at Spring Startup

After inspection, these are the parts most often needed before the first ride:

• Spark plugs — if not replaced last fall
• Oil and filter — if not changed before storage
• Battery — if more than 3–4 years old or not holding charge
• Wear ring or impeller — if pump inspection flagged wear
• Zinc anode — if more than 50% consumed
• Drain plug o-ring — if the original is hardened or deformed

Shop maintenance and service parts or use our engine parts section to find what you need. Most in-stock orders ship fast so you can get out on the water without waiting.

Bottom Line

Twenty minutes of inspection before the first ride of the season is the difference between a great day on the water and a frustrating breakdown. Run the checklist, address anything you find, and then go enjoy why you bought the ski in the first place.