Maintenance Matters - How To Winterize Your Mercury Outboard
For those of us who do not live in the Southern climates during the winter months, now is the time to prepare your Mercury outboard for its long winter nap. The most familiar cause of storage-related breakdown is water that is left in the engine block which in turn freezes. Ice will form, expand and then crack the cylinder block. This can lead to very costly repairs. Before storing your outboard for the winter we recommend performing the following simple steps.
Conditioning the Fuel:
The fuel treat is very important when winterizing your outboard. Do not be scared of using too much Fuel Conditioner
, as too little may keep the fuel stable for only a few months, leaving gooey varnish in the carburetors and using too much only puts a dent in your wallet that might save you from repair bills in the spring. Make sure you change the Water-Separating Fuel Filter
before starting the fuel treatment to ensure that any water in the system is removed. The fuel treatment is run in the boat for the last time, so it ends up throughout the fuel system and not just in the tank. Fogging Oil
comes in spray cans usually instead of quart bottles; however, we have found that draining the carburetor works better. Keep it running while you spray the fogging oil into the cylinders but do not over rev the engine past 1500 rpms. After you spray the fogging oil, turn off the engine and do not run it out of fuel especially if it is an oil-injected engine. On models that have drains on carburetors or vapor separator tanks (EFI Models) loosen drain screw on bottom of carburetor bowl or VST tank and drain all fuel from carburetors or VST. Remove the engine fuel filter and empty the fuel from the filter.
Run the fuel treatment through the engine for about 10-15 minutes then switch to the storage mix tank for another few minutes. The air silencer then is removed to spray a good dose of Engine Tuner
through the carburetors or fuel injection air tubes. The engine tuner washes carbon deposits from the cylinder heads, piston rings, piston tops and spark plugs. Once the engine tuner is sprayed in the appropriate places turn off the engine and let it sit for about a half hour. If this is the first time doing this, let the engine sit for a couple of hours to let the fluid work on the carbon deposits that may be baked-on. After this, start up the engine and spray in any unused tuner into the same places. Now, you are ready to use the fogging oil. Spray the fogging oil into the same orifices as the engine tuner. This oil coats the inside with a film that protects the metal surfaces and bearings from rust and condensation. The fluid may choke the engine or produce smoke but that is normal. You might need to rev the engine some to keep it running while you spray the fogging oil into the cylinders but do not over rev the engine past 1500 rpms. After you spray the fogging oil, turn off the engine and do not run it out of fuel especially if it is an oil-injected engine. Next, remove the all the spark plugs and insert a teaspoon of outboard oil into each cylinder. Then rotate the flywheel to distribute the oil in the cylinders after removing the kill switch to prevent the engine from starting. Then check the Tilt Fluid
and top off if needed. Now, tilt the engine down and drain the Gearcase Lubricant
. Fill the unit with fresh lubricant and replace the fill/vent plug gaskets if necessary. Make sure to Grease
the fittings on the engine which we recommend the swivel bracket, steering tube, tilt mechanism and cowling latches. Spray the powerhead and any wiring with Silicone Lubricant
. Also make sure you touch up any missing or chipped paint areas. Replace zinc anodes that are eroded. Then finally make sure you give the engine a coat of Protective Wax
. Make sure you cover the propeller exhaust outlets with a plastic bag to prevent pests and water from entering. Remove the battery and store in a cool place.
Before you begin winterizing your Mercury outboard, make sure to get a manufacturer specific service manual and read the section on storage preparation based on your make, model and year of engine. The costs of the supplies are minimal to protect your Mercury outboard during the winter and will keep your engine running smooth in the Spring.
Mercury Outboard Winterizing Checklist