Outboard Winterization & Storage FAQs

Can I start my engine momentarily out of the water?

No. NEVER start or run your outboard without water circulating through the cooling water intake in the gear case. Cooling water prevents damage to the water pump (running dry) and overheating of the engine.

Where do I find maintenance and lubrication information for my engine?

The Operation, Maintenance & Warranty manual outlines the typical maintenance and lubrication items. If your manual is missing or damaged, please order online or through any authorized Mercury dealer. Please have your outboard or sterndrive serial number before placing the order.

What should I do to prepare my outboard engine for out-of-season storage or prolonged storage?

The major consideration in preparing your outboard for storage is to protect it from rust, corrosion, and damage caused by freezing water that may be trapped in the engine. We recommend taking your engine to an authorized Mercury dealer to perform the work. Damage from improper storage procedures is not covered under the Mercury Marine limited warranty policy. If you choose to perform the storage procedure, follow the storage procedures outlined in your Operation, Maintenance & Warranty manual.

What is the purpose of using Storage Seal in my outboard engine?

Storage Seal Rust Inhibitor is a blend of corrosion-inhibiting additives designed to coat engine components during engine storage to reduce the formation of surface rust. Use Storage Seal Rust Inhibitor as directed in your Operation, Maintenance & Warranty manual, following the directions on the container.

Consult your Operation, Maintenance & Warranty manual for your specific engine. Use of storage seal is not recommended for all engines.

Why is Storage Seal Rust Inhibitor not recommended in the newer EFI and OptiMax engines?

Storage Seal Rust Inhibitor uses a thick base designed to protect the internal engine surfaces. In some applications we have seen a build up of the thick base inside the injectors, causing the injectors to stick or operate incorrectly. On these models we recommend Quickleen and 2-cycle engine oil as a replacement for Storage Seal Rust Inhibitor. Quickleen is used to clean the injectors. The engine oil lubricates, as well as prevents rust from forming. We continue to recommend Fuel System Treatment and Stabilizer to help prevent the formation of varnish and/or gum in the gasoline. Always follow the storage procedures outlined in your Operation, Maintenance & Warranty manual and Service manual.

What should I look for when draining my gear lube?

Inspect gear lubricant for metal particles (lubricant will have a 'metal flake' appearance). Drain lube into a clean pan/container. The presence of fine metal particles (resembling powder) in the gear lube indicates normal wear. The presence of metal chips in the gear lube indicates the need for gear housing disassembly and component inspection by an authorized dealer.

Note color of gear lubricant when draining. If the color is white or cream it MAY indicate the presence of water in lubricant. Gear lubricant which has been drained from a gear case recently in operation will have a yellowish color due to lubricant agitation/aeration. Gear lube which is mixed with assembly lubricant (Special Lube 101 or 2-4-C) will also be creamy white in color. This is normal and should not be confused with the presence of water. If water is suspected to be present in the gearcase, a pressure check of the gearcase should be completed by an authorized dealer. Pouring a portion of the gear lubricant into a glass jar and allowing the lubricant to settle will allow any water in the lube to separate and settle to the bottom of the jar.

The presence of water in gear lubricant indicates the need for inspection by an authorized dealer. The dealer will disassemble the gear housing and inspect the oil seals, seal surfaces, O-rings, water pump gaskets, as well as the gear housing components for damage.

Can I leave my lower unit or sterndrive empty of lubricant over the winter?

We do not recommend leaving a lower unit or sterndrive empty during storage periods. An empty oil cavity may allow moisture to collect on the gears, bearings and shafts. Rust will form when the moisture reacts with the air, damaging the internal components.

Note: If water was present when draining the gear oil, the lower unit or sterndrive should be inspected by an authorized dealer.

What is the purpose of the Corrosion Control Anode?

Your outboard has control anodes at different locations. An anode helps protect the outboard against galvanic corrosion by sacrificing its metal to be slowly eroded away, instead of the outboard metals.

Each anode requires periodic inspection especially in saltwater applications, which will accelerate the erosion. To maintain this corrosion protection, always replace the anode before it is completely eroded. Never paint or apply a protective coating on the anode, as this will reduce its effectiveness.

How can I prevent the propeller from sticking onto the shaft?

We recommend a liberal coat of one of the following Mercury Precision or Quicksilver Marine Lubricants on the propeller shaft: Special Lubricant 101, 2-4-C Marine Lubricant, or Anti-Corrosion Grease. These lubricants are available from any authorized Mercury Marine dealer.

Note: Always use the correct mounting hardware and torque the propeller nut to the correct specifications. Verify the propeller tightness after 20 hours of operation. DO NOT operate the boat with a loose propeller.

I accidentally reversed the battery connections when I reinstalled the battery. What potential damage could I have caused?

We strongly recommend that you have an authorized dealer inspect the vessel before returning it into service. The potential damage will vary from model to model. Although we try to design in protection for each component, limitations do exist.

The first item to check is the fuse or fuseable link. Most models have some type of protection in the circuits. You can replace the fuse with the correct size and test the system. If the fuse fails again, dealer involvement is recommended.

Other items on the engine that may be damaged include, but are not limited to the following: voltage regulators, rectifiers, tachometers, Electronic Control Module, isolation diodes and melted wiring. Boat-related items may include the following: radios, radar, lights, wiring, etc.

My dealer is recommending that I shrink wrap my boat before storage, are there any items affecting my engine that I should be concerned about?

Shrink wrap is a very effective method of protecting the boat during periods of storage; however, it is very important to ventilate the hull. Even in the driest conditions, without ventilation, the plastic cover will trap moisture. This moisture can create rust on some metal components, corrosion on others and mold/mildew on the carpet and upholstery. Always follow the manufacturer's recommendations for ventilation.

What should be done when storing boats with ethanol-blended fuels for extended periods?

Follow the instructions for normal storage preparation found in the Operation, Maintenance & Warranty manual. When preparing to store a boat for extended periods of two months or more, it is best to completely remove all fuel from the tank. If it is difficult or not possible to remove the fuel, maintaining a full tank of fuel with a fuel stabilizer added to provide fuel stability and corrosion protection is recommended. It is best to add the stabilizer and fuel treatment to the tank at the recommended dosage, run the engine for 10 minutes to allow the system to be cleaned, shut off the fuel valve to interrupt the fuel supply and allow the engine to run until it stops, and top off the tank until it’s full to reduce the amount of exchange with the air that might bring in condensation. Do not cap the tank vent and do not fill with fuel to the point of overflowing. Some extra space should be maintained in the tank to allow for expansion and contraction of the fuel with temperature changes. A partially full tank is not recommended because the void space above the fuel allows air movement that can bring in water through condensation as the air temperature moves up and down. This condensation could potentially become a problem.

Mercury Marine Quickstor can help maintain fuel systems in storage. It contains oxidation inhibitors to reduce oxidation and gum formation, metal-chelating agents to protect metal components from corrosion, water-absorbing agents to reduce the presence of free water, and dispersants to help suspend and disperse debris. When placing the boat back in service, be sure to reopen the fuel valve to the engine.