Outboards vary a lot: 2-stroke and 4-stroke, carbureted and fuel-injected. Your owner’s manual is the authority on procedures, intervals and fluids, and some steps, like fogging a fuel-injected engine, have model-specific instructions. If you’re unsure about any of it, have a marine technician do the layup.
Layup checklist
- Flush the cooling system with fresh water, especially after saltwater use, with flush muffs or the flush port as the manual describes.
- Take care of the fuel. Many manuals call for adding stabilizer to a nearly full tank and running the engine long enough for treated fuel to reach it. Some also call for draining the carburetor bowls or vapor separator. Follow yours.
- Fog the engine if the manual calls for it, using its procedure. Fogging coats internal parts to help resist corrosion during storage.
- Change the lower unit gear lube. Draining it lets you check for water (milky fluid) or metal on the drain plug magnet, either of which can point to a seal or gear problem. Refill from the bottom hole until lube comes out the top vent hole, then reinstall the plugs.
- Change the engine oil and filter on 4-stroke outboards, per the manual.
- Pull the propeller. Check it for damage, look for fishing line wrapped behind it on the shaft, grease the shaft as directed and reinstall it.
- Grease and inspect. Lubricate the grease points the manual lists, such as the swivel bracket and steering, and replace heavily worn sacrificial anodes.
- Let the water drain. Store the motor in the vertical, down position so water drains out of the cooling passages.
- Charge the battery, disconnect it, and keep it charged over the winter.
- Cover the motor and keep the boat as dry as you can.
Stored fuel is half the battle. The fuel storage and ethanol guide explains why ethanol blends and water don’t mix.
Frequently asked questions
Do I need to fog my outboard?
It depends on the engine. Some manuals call for fogging before storage and give a procedure, especially for carbureted engines. Some fuel-injected engines have their own storage procedure. Follow your manual.
Why is my lower unit gear lube milky?
Milky or creamy gear lube usually means water has gotten in, often past a worn seal. Have it checked before the next season.
Should I store my outboard tilted up or down?
Many manuals say to store it vertical, in the down position, so water drains from the cooling system. Follow your manual.
AMSOIL products for outboard layup
- AMSOIL Engine Fogging Oil. AMSOIL lists outboard motors among its applications and says its aerosol formula is “especially beneficial in applications with horizontal cylinder orientation, such as outboard motors.” Use your manual’s fogging procedure.
- AMSOIL 75W-90 100% Synthetic Marine Gear Lube. AMSOIL says it “delivers exceptional wear protection, even when contaminated with up to 15 percent water,” “protects against rust and corrosion” and “keeps seals soft to minimize water leakage.” AMSOIL lists it for “fresh- and saltwater applications that require 75W-90 or 80W-90 gear lube.” Check the spec your lower unit requires.
- AMSOIL Gasoline Stabilizer. AMSOIL lists boats among its applications and says it is “effective in ethanol-blended fuel.”
Product wording above is quoted or summarized from amsoil.com. Read each product’s label and data sheet for directions.
For engine oil, use AMSOIL’s outboard lookup or AMSOIL’s official lookup guide to see what AMSOIL lists for your motor.