Mid-October is when Illinois boaters start thinking about winter. Water left in an engine, old fuel and a dead battery can turn a great summer into an expensive spring. This checklist walks through the basics of winterizing and storing your boat, and shows where a professional can take over.
Always follow your engine and boat manufacturer's instructions. This is a general guide, not a substitute for your owner's manual.
Why winterizing matters in Illinois
Water expands as it freezes. Trapped in an engine block, a water pump, a livewell line or a heater core, it can crack metal and split hoses. Don't wait for the first hard freeze. Plan your haul-out for when you are done boating for the season.
At Quest, winter storage runs from mid-October to mid-April, so this is the time to book.
Step 1: Engine
Outboards and sterndrives
- Change the engine oil and filter, as your manual calls for.
- Change the lower unit or drive oil. Milky oil can signal water getting in.
- Flush the cooling system with fresh water, then protect it as your engine requires.
- Fog the cylinders to protect internal surfaces from corrosion.
- Replace fuel filters and water-separating filters.
- Check the gimbal ring and drive bellows.
Inboards and jet drives
The cooling system needs to be drained or filled with antifreeze, depending on the engine. Consult the manual or have a technician do it. Our technicians winterize inboard, sterndrive, outboard and jet-drive boats.
Step 2: Fuel
- Fill the tank, leaving room for expansion. A full tank leaves less room for condensation.
- Add a fuel stabilizer or conditioner, following the label.
- Run the engine long enough to circulate treated fuel through the system.
- Check fuel lines and the tank vent for leaks and cracks.
Ethanol-blended fuel can attract moisture over a long winter, so treating it is cheap insurance.
Step 3: Water systems
- Freshwater tank and lines: drain completely. Many boaters then run nontoxic marine antifreeze through the system.
- Livewells and baitwells: drain and open the plugs.
- Washdown pumps: run until empty or antifreeze comes out.
- Bilge: clean it out, then check the pump and float switch.
- Heads and holding tanks: pump out, flush and protect as directed.
- Drain plugs: remove them and store them where you won't lose them. Tape a note to the helm.
Step 4: Batteries and electrical
- Disconnect the batteries. Remove them if the boat will sit in an unheated space.
- Clean the terminals and check electrolyte levels on flooded batteries.
- Charge fully, and connect a maintenance charger if you will keep power available.
- Spray terminals and connections with a corrosion inhibitor.
- Remove electronics, cushions and valuables, or at least take the electronics home.
Step 5: Clean, protect and inspect
- Wash the hull and deck. Scrub off waterline scum before it hardens.
- Wax the gelcoat, and treat vinyl and canvas.
- Remove food, water and anything mice enjoy. Prop cabin doors and lockers open for airflow.
- Inspect the trailer. Check tires, bearings, lights and brakes.
- Write down jobs you noticed during the season so they are done before spring.
Shrink-wrap vs. indoor storage
The right choice depends on your boat, your budget and how much room is available.
Outside storage with shrink-wrap
- Available year-round, priced by boat length.
- Shrink-wrap keeps snow, rain and debris off your boat, and vents let air flow.
- Recommended by Quest for winter. Outside storage is priced by length.
Inside storage
- Protects the boat from weather, ice and sun.
- Quest's inside storage includes retrieval, set and relaunch. Boats can be on a trailer or blocked on stands.
- Wide boats stored off a trailer may not fit, and premium inside space is very limited and needs Quest approval.
Ask about your options on our boat storage and off-season service page, where you can build an itemized winter quote online.
Do it yourself or hire it out?
Many owners handle the simple jobs, such as fuel stabilizer and cleaning, and leave the engine work to a technician. Hiring a pro makes sense if you have an inboard or sterndrive, a complex water system or limited time.
Our team handles winterization and shrink-wrapping, along with spring summerization and haul-out and launch. See marine service and parts for the full menu. Service is available Tuesday to Saturday, 8:00 AM to 5:00 PM.
What a Quest winterization includes
- Basic: drain water, run on antifreeze, drain and fog, disconnect batteries.
- Full service: everything in Basic plus, as applicable, engine oil and filter change, drive oil change, gimbal ring torque check, fuel conditioner and one fuel filter.
A hands-off alternative: valet service
If you would rather not trailer, launch or store at all, ask about our boat valet service. It includes covered indoor storage, launch, retrieval and a wash-down after each trip.
Winterizing other toys
We also store jetskis (a trailer is required), golf carts and eBikes. The eBike storage includes a tune-up, so your bike is ready in spring.
Spring checklist preview
- Reinstall drain plugs first.
- Reconnect charged batteries.
- Check hoses, clamps and belts.
- Check the safety gear: life jackets, fire extinguisher, flares and lights.
- Test the engine before launch day.
Book your winter service
Winter slots fill up. Call 815.433.2200 or visit Quest Watersports at 1851 Old Chicago Rd, Ottawa, IL 61350, Tuesday to Saturday, to schedule your haul-out and winterization.
FAQ
When should I winterize my boat in Illinois?
Before the first hard freeze. Quest's winter storage season runs from mid-October to mid-April, so booking in October is a good idea.
Do I need fuel stabilizer?
It is a smart precaution. Treat the fuel according to the label and run the engine so the treated fuel circulates.
Is shrink-wrap or indoor storage better?
Indoor storage protects from the elements, while outside storage with shrink-wrap is a common alternative. Quest recommends shrink-wrap for outside winter storage.
Can Quest winterize my boat for me?
Yes. We winterize inboard, sterndrive, outboard and jet-drive boats and can shrink-wrap, wash and store them.
What should I do with my battery?
Disconnect it, clean the terminals, charge it fully and store it where it will not freeze, or use a maintenance charger.
Can I just pick up my boat after service?
Yes, with the service-only option. Quest asks you to pick it up within 2 weeks of notice, after which a daily storage fee applies.