How to Winterize an Outboard Motor: A Step-by-Step Checklist for Canadian Boaters

To winterize an outboard motor, you stabilize the fuel, flush the engine and fog the cylinders. You also change the oil and gear lube, grease the fittings and store the motor upright. Always check your owner’s manual first. Steps vary by engine model.

This guide walks you through each step. It also lists the supplies you need.

Why Winterizing Matters

Winter is hard on outboards. Cold weather, moisture and old fuel cause most spring problems.

Here is what can go wrong without proper care:

• Freeze damage: Water left in the engine can freeze and crack parts.
• Bad fuel: Gas breaks down over time and can gum up the system.
• Corrosion: Moisture attacks metal inside the engine.
• Hard starts: Neglected engines often struggle in spring.

An hour of work now can save you a costly repair later. It also means a faster, easier launch next season.

Before You Start

Gather your tools and supplies first. This keeps the job smooth and quick.

Read your owner’s manual. Each engine is different. The manual is your best guide for your motor.

Work in a safe space. Choose a ventilated area. Keep a fire extinguisher nearby. Our fire extinguishers are a good addition to any shop or garage.

Not comfortable with the work? A qualified marine technician can handle it for you.

Your Winterizing Supply List

Here is what most boaters need. Check your manual for exact specs.

Step-by-Step Outboard Winterization

Step 1: Add Fuel Stabilizer

Old gas is a top cause of spring trouble. It can leave gum and varnish in the fuel system.

Add a fuel stabilizer to a nearly full tank. Follow the label for the right amount. Then run the engine for several minutes. This moves treated fuel through the whole system.

Browse our fuel additives and storage kits to find the right product.

Tip: A full tank leaves less room for moisture to build up.

Step 2: Flush the Engine With Fresh Water

Salt, sand and debris build up inside your cooling system. Flush them out before storage.

Use a motor flusher and a garden hose. Follow your manual for the right method. Never run the engine without water.

This step matters most if you boat in salt water. Salt left behind speeds up corrosion.

Step 3: Fog the Engine

Fogging oil coats the inside of the cylinders. It forms a thin layer that helps block rust and corrosion.

Spray fogging oil as your manual directs. Many owners do this while the engine runs. Others spray into the spark plug holes. Use the method your maker recommends.

Step 4: Change the Engine Oil and Filter

Used oil holds acids and moisture. You don’t want it sitting in your engine all winter.

For a four-stroke motor, drain the oil while it is warm. Replace the filter. Then add fresh oil that meets your engine’s specs.

Find what you need in our 4-stroke outboard oil and oil filters collections.

Own a two-stroke? See our 2-cycle outboard oil options. Also check our oil change systems and pumps to make the job cleaner.

Step 5: Change the Gear Lube

The lower unit holds gear lube. Water can sneak in through worn seals. Winter cold can then do serious damage.

Drain the old lube into a clean pan. Look at the colour. Milky or cloudy lube may mean water got in. If so, have a technician check your seals.

Refill with fresh gear lube. Use the type your manual lists. A gear lube pump makes refilling easy.

Step 6: Grease the Fittings and Moving Parts

Grease protects parts from moisture and wear. Check the steering, tilt and swivel points. Look at the throttle and shift cables too.

Apply marine grease where your manual says. A grease gun helps you reach tight spots.

You can also use penetrating lubricants on stiff or sticky hardware.

Step 7: Inspect and Replace Wear Parts

Winter is a great time for a full check. Replacing parts now saves rushed repairs in spring.

Look closely at these parts:

• Spark plugs: Replace worn plugs. Browse spark plugs and spark plug wires.
• Water pump impeller: Impellers wear over time. Check our impellers.
• Propeller: Look for nicks, bends or fishing line. See our boat propellers.
• Anodes: These protect your engine from corrosion. Replace them when they are worn. Shop anodes.
• Fuel lines and primer bulb: Look for cracks or soft spots. See fuel line assemblies and primer bulbs.

Step 8: Drain Water and Check the Fuel Filter

Trapped water can freeze and crack parts. Make sure your engine drains fully.

Store the motor upright if your manual says so. This lets water run out of the lower unit and cooling passages.

Also inspect your fuel filter. Water or debris in the bowl is a warning sign. Look at our Racor gasoline fuel filters and spin-on gasoline filters.

Step 9: Care for the Battery

Batteries lose charge in the cold. A dead battery in spring is a common frustration.

Remove the battery if you can. Store it in a cool, dry place off the floor. Keep it charged over winter. Check its level with a battery meter.

Need a new one? Browse our marine batteries.

Step 10: Clean, Cover and Store

Wash the engine with fresh water. Wipe it down. Touch up any scratches or bare metal with engine paint.

Then add a motor cover. Choose one that lets air flow. A tight, sealed cover can trap moisture.

Store the motor somewhere dry if you can. Add a lock for peace of mind. See our outboard motor locks.

Don’t Forget the Rest of Your Boat

Your motor is only one part of the job. Protect the hull and deck too.

• Cover it: Browse our boat covers and boat cover supports.
• Shrinkwrap it: See our shrinkwrap and accessories.
• Support it: Use sturdy boat stands for stored boats.
• Fight dampness: Add a dehumidifier or moisture absorber inside the cabin.

Is your boat staying in the water? Read our guide on marine cabin heaters to keep it dry and warm.

Printable Winterizing Checklist

Use this quick list as you work.

1. Read your owner’s manual.
2. Add fuel stabilizer and run the engine.
3. Flush the engine with fresh water.
4. Fog the cylinders.
5. Change the engine oil and filter.
6. Change the gear lube and check for water.
7. Grease all fittings.
8. Inspect plugs, impeller, prop and anodes.
9. Drain water and check the fuel filter.
10. Charge and store the battery.
11. Clean, cover and store the motor.

Common Winterizing Mistakes to Avoid

Even experienced boaters slip up. Watch out for these.

• Skipping the manual. Steps differ between engines.
• Using old fuel. Always stabilize your fuel.
• Forgetting the lower unit. Water in the gear case causes real damage.
• Sealing the motor under a tight cover. Trapped moisture leads to rust.
• Putting it off. Don’t wait for the first hard freeze.

Shop Winterizing Supplies at Steveston Marine

We have served Canadian boaters since 1941. We stock over 10,000 marine products, including everything on this list.

Looking for savings? Check our Sale page. You can also browse Clearance. Clearance items are final sale.

We ship across Canada. Orders over $120 qualify for free shipping, with some exceptions. Read our delivery information for details.

Have a question about your motor? Contact our team. You can also stop by one of our store locations. For more guides, visit our DIY & Learn page.

Frequently Asked Questions

When should I winterize my outboard motor?

Winterize before the first hard freeze. Many Canadian boaters do it in October or early November. Check your local weather and plan ahead.

Do I need fuel stabilizer for winter storage?

Yes, in most cases. Stabilizer slows fuel breakdown during storage. Add it to a nearly full tank. Then run the engine so treated fuel reaches the carburetor or injectors.

What is fogging oil used for?

Fogging oil coats the cylinder walls with a thin protective layer. It helps prevent rust and corrosion while the engine sits. Follow your manual for the right method.

Should I store my outboard upright or tilted?

Most makers recommend storing it upright. This helps water drain from the lower unit and cooling system. Check your manual to be sure.

Can I winterize a two-stroke the same way as a four-stroke?

The steps are similar, but there are differences. Two-strokes don’t have an engine oil sump to change. They still need fuel care, fogging, gear lube and lubrication. Always follow your engine’s manual.

Can a technician winterize my motor for me?

Yes. A qualified marine technician can handle the full job. This is a good choice if you want expert help or lack the tools.

Final Thoughts

Learning how to winterize an outboard motor takes little time and skill. Stabilize the fuel, flush, fog, change your fluids and store it right. Your engine will thank you in spring.

Ready to start? Browse our fuel additives, fogging oils and gear lube today. Or contact us and we will help you find the right supplies.