Winterizing an outdrive is a crucial process that protects your boat's propulsion system from the damaging effects of freezing temperatures. It involves several key steps to ensure all water is displaced and components are properly lubricated and protected during storage.
The primary reason to winterize an outdrive is to prevent costly damage caused by freezing water. Water trapped within the outdrive's cooling passages, gearcase, or other components can expand when it freezes, leading to cracked blocks, damaged pumps, broken hoses, and other severe issues. Proper winterization also protects against corrosion and general wear and tear during the off-season.
Methods for Outdrive Cooling System Winterization
The method for circulating antifreeze into the cooling system is a critical part of outdrive winterization.
- Professional Dealer Method: A dealer will immerse the outdrive in a large tank of antifreeze solution and then run the engine to circulate the antifreeze into the cooling system. This ensures thorough displacement of water.
- DIY Owner Method: A better option for the DIY owner is to use a gravity flow device that connects with a garden hose. This device allows you to feed antifreeze directly into the cooling system. It is very important to displace all water from the cooling system regardless of the method used, to prevent freezing and damage.
Comprehensive DIY Outdrive Winterization Steps
Beyond just the cooling system, a complete outdrive winterization involves several other vital tasks.
1. Flush and Circulate Antifreeze Through the Cooling System
This step is paramount to prevent freeze damage.
- Preparation: Ensure your boat is in a safe location, ideally on a trailer or dry storage.
- Connecting the Device: Attach a gravity flow device (often called a 'winterizing flush kit' or 'ear muffs' with a built-in reservoir for antifreeze) to the outdrive's water intake. Connect a garden hose to the device if required for initial flushing, or directly to the antifreeze reservoir.
- Flushing: Briefly run the engine in neutral to flush the system with fresh water (if using ear muffs) to remove any salt, dirt, or debris.
- Antifreeze Circulation:
- Shut off the engine.
- Connect the gravity flow device to a container of non-toxic marine-grade antifreeze (propylene glycol). Ensure the hose from the device is submerged in the antifreeze.
- Start the engine (in neutral) and let it idle. The engine's raw water pump will draw the antifreeze into the cooling system, displacing the water.
- Continue running the engine until you see the antifreeze discharge from the exhaust outlet, indicating that the system is fully flushed with antifreeze.
- Shut off the engine immediately after you observe the antifreeze flowing out.
2. Change Lower Unit Gear Lube
This step prevents water intrusion damage and ensures proper lubrication.
- Drain Old Lube: Place a drain pan beneath the outdrive. Locate and remove the vent plug (top) and drain plug (bottom) on the lower unit. Allow all the old gear lube to drain completely.
- Inspect Lube: Examine the drained gear lube for signs of water (milky appearance) or metal shavings (indicating internal wear). If water is present, have the seals inspected and repaired by a professional.
- Refill: Using a gear lube pump that connects to the lower drain hole, pump new, marine-grade lower unit gear lube into the unit until it overflows from the vent hole.
- Replace Plugs: Reinstall the vent plug first, then remove the pump and quickly replace the drain plug.
3. Grease All Fittings and Moving Parts
Proper lubrication protects against corrosion and ensures smooth operation.
- Locate Zerk Fittings: Identify all grease zerks on the outdrive. Common locations include the gimbal bearing, U-joints, steering arm, and pivot points. Consult your owner's manual for exact locations.
- Apply Grease: Using a marine-grade grease gun, apply fresh waterproof grease until you see old grease or water being expelled.
4. Inspect Bellows and Anodes
These components are crucial for the outdrive's integrity and protection.
- Bellows Inspection: Visually inspect the exhaust, shift, and drive shaft bellows for any cracks, tears, or signs of dry rot. Damaged bellows can lead to water intrusion.
- Anode Inspection: Check the sacrificial anodes (zincs) on the outdrive for corrosion. If an anode is more than 50% depleted, replace it to ensure continued galvanic corrosion protection.
5. Remove and Inspect Propeller
This prevents the prop from seizing on the shaft and allows for inspection.
- Removal: Remove the propeller, thrust washer, and any associated hardware.
- Inspection: Check the propeller for dings, bends, or other damage.
- Shaft Greasing: Clean the propeller shaft and apply a generous coat of marine-grade waterproof grease to prevent corrosion and make future removal easier. Reinstall the prop or store it separately.
6. Position the Outdrive for Storage
The final position of the outdrive is important for proper drainage.
- Lower Position: Always store the outdrive in the fully down (trimmed in) position. This allows any residual water to drain completely from the exhaust and lower unit, preventing water from collecting and freezing.
Outdrive Winterization Checklist
| Step | Detail | Importance |
|---|---|---|
| 1. Cooling System Antifreeze | DIY: Use a gravity flow device to circulate marine-grade antifreeze, displacing all water. Professional: Outdrive immersed, engine run to circulate antifreeze. | Prevents freezing and cracking of internal water passages. |
| 2. Change Lower Unit Gear Lube | Drain old lube, inspect for water/metal, refill with fresh marine-grade gear lube. | Protects gears from corrosion and ensures proper lubrication. |
| 3. Grease All Fittings | Apply marine-grade grease to all zerk fittings (e.g., gimbal bearing, U-joints, steering). | Prevents rust and corrosion, ensuring smooth operation. |
| 4. Inspect Bellows | Check exhaust, shift, and drive shaft bellows for cracks or damage. | Prevents water intrusion into the transom assembly and boat. |
| 5. Inspect & Replace Anodes | Check sacrificial anodes for corrosion; replace if more than 50% depleted. | Protects outdrive from galvanic corrosion. |
| 6. Remove & Inspect Propeller | Remove prop, inspect for damage, clean shaft, and grease propeller shaft. | Prevents prop seizing, allows shaft inspection, and protects components. |
| 7. Store Outdrive Down | Ensure the outdrive is trimmed fully down (in) for storage. | Facilitates complete water drainage, preventing ice damage. |
By meticulously following these steps, you can ensure your outdrive is properly protected against the harsh realities of winter, leading to a smooth start to the next boating season.
