Putting your ski in storage for any length of time including winter storage is never fun but very important to take the time to do it properly.
Step 1: Keep the engine from freezing and cracking.
The most important part of winter storage in a cold climate is to make sure you get all of the water out of the engine. Water left in cavities can freeze and crack the engine block or exhaust system.
Most people in cold climate will start the ski dry and rev the engine several times to clear out water in the exhaust pipe.
Draining water out or replacing water with RV antifreeze for the winter is a must if you are storing in an area that the temperature goes below freezing. You can accomplish this a couple ways. You can pull hoses and fitting off of the engine and exhaust to drain the water out, you can blow compressed air through the passages to remove water, or you can run the engine while pouring or pumping anti freeze through the flush adapter. Seadoo 4 Tec skis have closed cooling systems with anti freeze already in the engine block so it will only be necessary to winterize the cooling passages in the exhaust system.
Step 2: Lubricate all internal parts.
On all 4 stroke watercraft it is important to change the engine oil before storage to prevent the engine components from sitting in contaminated oil all winter. Coat all of the internal engine components with oil to prevent corrosion.
This can be accomplished 2 ways. You can spray fogging oil through the air intake while the engine is running or you can spray some fogging oil in each cylinder through the spark plug hole and bump the engine over a few times.
Either of these operations should be the last thing you do before you are not going to start the engine anymore before storing.
Step 3: Lubricate and Maintain Drive Line and Jet Pump.
Most jet skis have several places that need to be greased. These are usually located and related to the drive line of the ski. (Refer to owners manual)
Another area often over looked is the jet pump. Older Seadoo models have oil in the pump that needs to be changed. This is a simple process that can be done by most do it yourselfers. At the same time you are maintaining the jet pump you can inspect your wear ring and impeller for damage.
Step 4: Maintain your Trailer.
At the end of each season you should take the time to inspect and maintain your trailer. It only takes a short time and will save you a lot of trouble the next season. Nothing will ruin a great day of riding faster than being stuck on the side of the road with a broken trailer.
Check all of your bunk boards and carpet to make sure you do not damage your hull.
Check your bow stop and winch strap to see if they need replaced. Make sure to lubricate the winch itself.
Check and grease the trailer jack at the front of the trailer. Most models the top cap comes off to expose the gear inside so it can be greased.
Check all of your lights and replace if necessary. If you are feeling real energetic you can remove the bulbs and spray the sockets with a little WD40 to prevent corrosion.
Most importantly grease the wheel bearings, check the tries for any damage or dry rot, and check all your springs and hardware for rust and corrosion.