Essential Guide to Winterizing Your Outboard Engine

As winter approaches, properly winterizing your outboard engine becomes crucial for preventing costly damage and ensuring reliable performance when spring arrives. This comprehensive guide will walk you through the essential steps to protect your investment during the cold months ahead.

Fuel System Protection

The fuel system requires special attention during winterization to prevent ethanol-related issues and fuel degradation. Start by filling your fuel tank to about 95% capacity, leaving room for expansion. Add a quality marine fuel stabilizer according to the manufacturer’s specifications, typically 1 ounce per 10 gallons of fuel. Run the engine for at least 15 minutes to ensure the treated fuel circulates through the entire system.

Change the Lower Unit Oil

Changing the lower unit oil is a critical step that’s often overlooked. Remove the lower and upper drain screws and check for any water contamination, which appears milky. If you spot contamination, this could indicate seal problems that should be addressed before storage. Replace with fresh marine-grade gear oil, ensuring proper fill levels.

Engine Fogging

Protecting internal engine components from corrosion requires proper fogging:

1. Start the engine in a well-ventilated area
2. Remove the air intake cover
3. Spray fogging oil into the carburetor or air intake while the engine runs
4. Continue spraying until the engine stalls from the fogging oil
5. Replace the air intake cover

Flush and Drain the Cooling System

Even small amounts of water left in the cooling system can cause serious damage when frozen:

1. Flush the system with fresh water using muffs or flush ports
2. Run the engine briefly to circulate antifreeze through the cooling passages
3. Allow all water to drain completely
4. Tilt the engine up and down several times to ensure complete drainage

External Protection

Protect external components with these steps:

1. Clean all external surfaces thoroughly
2. Apply corrosion inhibitor to electrical connections
3. Lubricate all grease points, linkages, and cables
4. Remove the propeller and grease the shaft
5. Check the sacrificial anodes and replace if more than 50% eroded

Battery Maintenance

Remove the battery and store it in a cool, dry location on a trickle charger or maintenance charger. Clean the terminals and apply dielectric grease to prevent corrosion. Check electrolyte levels in conventional batteries and top off with distilled water if needed.

Control Cable Care

Inspect all control cables for proper operation and signs of wear. Lubricate throttle, shift, and steering cables with appropriate marine-grade lubricant. This prevents moisture accumulation and ensures smooth operation in spring.

Storage Position

Store the engine in its normal running position or slightly tilted down. Avoid storing in a fully tilted position, as this can cause lubricant to drain from vital components. If storing outdoors, use a high-quality engine cover to protect from the elements.

Additional Considerations

Take time to perform these supplementary tasks:

• Replace the water pump impeller if it’s more than 2 years old
• Inspect and replace spark plugs if necessary
• Check and tighten all mounting bolts
• Document any issues needing attention in spring
• Take photos of current engine condition for reference

Spring Preparation

While winterizing, create a spring commissioning checklist. Note any parts that may need replacement or maintenance before the next season. This proactive approach helps ensure a smooth start when boating weather returns.

Professional Service Option

If you’re not comfortable performing these tasks or lack the necessary tools, consider professional winterization service. Many marine mechanics offer comprehensive packages that include all necessary steps plus inspection for potential issues.

Following these winterization procedures protects your outboard engine investment and helps avoid costly repairs. While the process may seem time-consuming, it’s far less expensive and troublesome than dealing with damage caused by improper winter storage. Take the time to winterize correctly, and you’ll be rewarded with reliable performance when you’re ready to get back on the water.