Why is a thorough recommissioning essential?
Whether it's your SEADOO or your WILLIAMS SPORTJET, TURBOJET, or MINIJET tender, equipped with a ROTAX engine, after several months of winterization, your craft cannot be put back in the water without a complete inspection. Rotax ACE engines are robust, but seals, filters, batteries, and hydraulic circuits degrade during the storage period. A methodical check prevents breakdowns at sea and extends the life of your machine.
Here are the 10 essential checks to perform before the first outing of the season.
1. Battery: charge and condition
This is the starting point. Check the voltage of the battery with a multimeter: it should show 12.6 V minimum at full charge. If it is below 12 V, recharge it with a suitable charger (CTEK type or equivalent). Inspect the terminals for any signs of oxidation and clean them if necessary. A battery older than 3 years deserves to be preventively replaced.
2. Engine oil level and quality
Check the oil level with the dipstick. The oil should be clean, clear amber. If it is black or emulsified (milky appearance), proceed with an oil change immediately. For Rotax ACE 903, 1503, and 1603 engines, use XPS 5W40 synthetic BRP oil. Take advantage of the recommissioning to also replace the oil filter if it hasn't been done since last season.
3. Oil filter
The oil filter must be replaced with each oil change, i.e., every 50 hours or once per season. Check for leaks around the filter cover. OEM BRP reference: 956744. Consult our oil filter replacement guide for the complete procedure.
4. Cooling system
The Rotax ACE engine is water-cooled. Check that the hoses are not cracked, split, or porous. Check the hose clamps. Make sure the water intake filter (strainer) is not obstructed by debris. A faulty cooling system can lead to engine overheating in minutes.
5. Wear ring and impeller
Inspect the wear ring by reaching into the intake grate, or when removing the pump unit. A clearance greater than 1.5 mm between the impeller and the ring indicates excessive wear. Also check the condition of the impeller blades: any chipping significantly reduces performance. Find compatible wear rings in our store.
6. Spark plugs
Remove the spark plugs and inspect their condition. A healthy spark plug has a clean, light brown electrode. Black deposits indicate a rich mixture, white deposits indicate overheating. Measure the gap: it must conform to manufacturer specifications (generally 0.7 to 0.8 mm for Rotax ACE). Replace spark plugs every 2 years or 100 hours.
7. Steering and reverse system
Test the steering by hand: it should be smooth and without hard spots. Check the condition of the steering and reverse cables (sheath, outer sheath, fasteners). Lubricate the joints with marine grease. Check the proper functioning of the reverse gear if your model is equipped with one.
8. Hull and compartments
Inspect the hull underneath and over its entire surface: cracks, impacts, delamination. Open all compartments and check for stagnant water or abnormal moisture — a possible sign of infiltration. Check the condition of the hatch and hood seals. Make sure the hull drain plug is securely in place and watertight.
9. Fuel and fuel system
If fuel remained in the tank during winterization without a stabilizer, it may be degraded (oxidation, deposits, strong odor). In this case, drain the tank and refuel with fresh fuel. Check the condition of the fuel filter and fuel lines. Check for leaks at the tank and connections. Check the proper functioning of the fuel pump by listening! Indeed, it should emit a slight whistle when you turn on the ignition, which is a sign that the fuel is pressurizing correctly.
10. Dockside test before launching
Before putting the jet ski back in the water, perform a dockside engine test with a hose connected to the garden hose intake ("ear muffs" or flush adapter). Start the engine and let it run for 1 to 2 minutes maximum. Check for cooling water ejection, absence of abnormal smoke, and listen for any suspicious noises. Check oil levels one last time after the test.
Conclusion
A careful recommissioning means a serene season. These 10 checks only take half a day and save you from costly breakdowns in the middle of navigation. Find all compatible Sea-Doo Spark and WILLIAMS maintenance parts (oil filters, wear rings, spark plugs) directly in our rotaxtenderparts.com store.
