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I often hear people say they never stored their motor in the past, why should they spend time and money doing something if it doesn't need it? The reality is, improper off season storage of an outboard motor has cumulative effects. During the off season, engine components can and do rust — the extend of which depends on what fuel mixture was last running in the engine, and the heat and humidity the engine is stored in. When rust forms, it creates pitting in the metal — specifically, the hardened steel surfaces the needle bearings in modern engines utilize. When the engine is started each spring, the rust is washed away and the pitting remains until one year, the bearing calls it quits and a rod exists through the side of the block. Many people don't associate rod failure with poor engine storage because the failure often takes place in the middle of summer and no connection is made to poor storage practices. Naturally, when this happens, they'll blame the engine manufacturer instead of placing the blame squarely where it belongs.
Modern engines, especially oil injected ones, have so little oil in them when the key is turned off, that maintenance issues are no longer an ‘if', but a ‘when' scenario. It doesn't take much math to figure out that current oil injected outboards can run on as little as one cup of oil to five gallons of gasoline. Given that current oils are designed to lubricate and burn cleanly, (not coat and protect from rust), it's more important than ever to properly store your outboard motor and protect your investment. Bearing issues aside, the are other items that need to be addressed too so let's get started:

All Models

To prevent condensation in the fuel tank and prevent breakdown of the fuel during storage, let's fill those fuel tanks with gas and add the appropriate amount of fuel stabilizer (follow directions on the label for storage). So why stabilize the fuel? The current shelf life of today's fuels is pegged at about three months. After that, the additives begin to separate, the octane level drops, and the gas begins the process of ‘going bad' and varnishing fuel system components (including gumming up the carb). Since most of us are going to lay the boat up for about 6 months, this step is just as important as the others in ensuring trouble free boating next summer.

Bring the engine up to operating temperature and allow enough time for the stabilizer to reach the carbs (10-15 minutes at idle, or 3 minutes at wide open throttle). Since portable steel tanks were used for many years with outboard motors, visually inspect for water in the bottom of any steel tank(s) using a flashlight. If water is found (round globs on the bottom of the tank), dump the tank and flush thoroughly. If rust is evident, the tank should be disposed of and replaced with a new plastic style. In the water, or on a pair of earmuffs (to supply the engine with water), do the following:

For carbureted engines with a maintenance valve (newer OMC's):
Attach engine fogger to maintenance valve fitting (looks like a tire air valve -- check your owners manual for location). Start engine and bring RPM to about 1500. Push and hold the release button on the fogger and continue holding until a steady thick white smoke appears out the exhaust. Depending on the size of the engine, this should consume about a half a can of fogging oil. Turn the engine off immediately after you're finished fogging (to ensure as much fogger as possible remains in the engine) and remove the fogger from the maintenance valve.

For carbureted engines without a maintenance valve (common for most brands and years):
Depending on the engine make a model, there is either removable plastic plugs in the breather cover, small holes in the breather, or no breather at all. Since we have to spray the fogger directly into the carb throats, determine how you are going to gain access to them before you get started. If the engine is equipped with removable plugs, pop them all out now. If there are pre-drilled access holes, locate them and ensure you have as many holes as there are carb throats. If there are no plugs or pre-drilled holes, simply remove the breather cover to gain access. Install the straw adapter that came with the can of fogging oil and bring the engine up to 1500 RPM. While holding down on the release button of the fogger, spray fogging oil into each carb throat for a 3-5 seconds, then move onto the next throat. Keep going from carb to carb until a steady thick white smoke appears out the exhaust. Depending on the size of the engine, this should consume about half to 3/4 of a can of fogging oil. Turn the engine off immediately after you've finished fogging (to ensure the fogger remains in the engine).

All Models

Pull the boat out of the water (or remove the ear muffs) and keep the motor in a vertical position for at least ten minutes to ensure all water is drained from the block and passages (outboard motors are self draining and require no anti-freeze for storage). If possible, the engine should be stored in an upright position in the coldest condition possible (rust processes are slowed considerably at low temperatures, and no humidity to promote rust exists below freezing). The worst place to store your outboard is in your basement beside your furnace — high humidity and warmth will seize an engine in no time.
For those that may be storing for extended periods of time or in warm humid conditions, you might want to remove the spark plugs and squirt some additional 2 stroke engine oil or fogger into the cylinders, then roll the engine over by hand to thoroughly coat everything. Re-install the plugs to minimize condensation during the storage period.

Storing the carbs wet or dry?
Today's carburetors utilize many neoprene, rubber, and alcohol resistant materials. Draining the fuel system for storage can put these parts at risk by allowing the materials to dry out and crack. Most (if not all) manufacturers recommend the carbs be left ‘wet' — that is, they fuel is stabilized and left in the carb during the storage period. If the engine will be stored on its side, or will be traveling in a vehicle before lay-up, it may be best to drain the fuel system by disconnecting the fuel line while fogging the engine, then continue to fog until the engine runs out of fuel (choking just as it's dying will get the last bit of fuel out).

Gearcase Oil Change

At a minimum, we want to inspect the gear oil before storage because if water is present in the gearcase, it can freeze and crack the case when the temperature falls (not to mention your gears and bearings will rust too). As long as we're there anyway, why not change it now too so we have one less thing to do in the spring when we're busy trying to get back on the water as fast as we can?

Most brands have easy to find drain and vent screws. The drain/fill screw is usually located just beneath the ‘bullet' shape of the gearcase, while the vent/overflow screw is located just above the anti-ventilation plate (often incorrectly called the cavitation plate). Pull both screws and inspect the quality of the gear oil while it drains. WARNING: Do not pull the screw with the philips (star) headed screw. This part (the pivot pin) cannot easily be re-installed properly without disassembling the gearcase.

White or creamy oil indicates you have water contamination. If you find this condition, have a dealer perform a pressure and vacuum test on the gearcase. It should go without saying that if nothing but water comes out of the oil cavity, you're likely in need of something more than seals. Grey oil usually indicates a failure of some sort has occurred in the lower unit (chipped gears or bearing failure). In some cases, prolonged use of the same oil can lead to the same oil condition. If you find you're oil is grey with a very strong odour, see your dealer for service and advice. Black oil indicates all is OK, you're just a bit overdue on your change cycle. As a benchmark for future the future, gear oil should be changed every 50-100 hours of operation, or at least once annually — whichever comes first. Many gearcases utilize a magnet on the drain screw. It's is normal to see a collection of fine metals filings, but if you find metals chunks, it's best to have the unit looked at by a professional.

Which gear oil to use?
If you have an electric shift gearcase (common in the sixties), you need a special oil called OMC Premium Blend (used to be called ‘Type C'). Failure to use this oil will result in a failure of the electromagnetic shift system this system utilizes.

All other gearcases (including hydro-electric shifts) will operate on a hypoid 90 weight oil. OMC's Hi-Vis brand fits the bill nicely, and if you really want to extend gear life and protect if the unit is contaminated with water, I strongly recommend OMC's HPF synthetic gear oil. When in doubt, follow your engine manufacturers recommendations.

Re-filling the gearcase (do NOT leave it empty for the storage period):
To start with, let's install new gaskets or o-rings on our fill screws (cheap insurance to save grief down the road). Next, many manufacturers supply their oil in soft squeezable bottles, or optional hand pumps can be purchases for larger containers. Whatever method you choose, fill from the bottom hole until it comes out the top hole. Install the top screw, then remove filler from the bottom and quickly install the screw there as well. Torque the screws and wipe off the excess oil. Speaking of excess oil, please make sure you dispose of the old oil in an environmentally responsible manner.


I strongly recommend the batteries be removed entirely from the boat, but if you're one of those types who leaves them in, at least disconnect them (ALL CABLES). Turning the battery switch off is not good enough. Next, clean the terminals and tops of the batteries as any moisture or dirt will allow cross discharge between the posts. The batteries should be stored in a cool, dry place. Warm humid storage will promote cross discharge through the air. Charge the batteries at least every two months. Watch your water levels and top up as necessary.

FYI, I store over 250 batteries in an outdoor building (unheated). I ensure the batteries are fully charged prior to storage, and charge them only once in January. I have yet to lose a battery over the winter and have had some last up to 9 years before I gave it the boot. A good battery will give a least five full years of service. One more thing to try and kill an urban legend: Storing your battery on a concrete floor will not hurt your battery.


Where I live, the water is clear and the algae growth minimal (God's country). We don't even bother cleaning the boats until spring, and even then, a good scrubbing and spray brings them back to nearly new.

I will recommend hydrochloric (muriatic) acid for those stubborn stains and water lines, but be careful -- that stuff is mighty toxic to the lungs and corrosive to skin. Apply it with a paint tray and roller, let stand for 10 minutes, then rinse off. Water will quickly neutralize the acid. Don't forget to store your boat bow high and remove all drain plugs. It would be a shame if you found a split hull in the spring (well, not for me and my fellow marina operators ).

If possible, store your tops in a warm place at home. While the new synthetics are quite durable, the older vinyls and viewtex (clear plastic) don't like the cold. Obviously, a good wash and rinse is recommended before storage. If the boat is going to be outside, it's not that tough (or expensive) to build a wooden frame (using the tent pole method with bailing twine to support). A suitable sized tarp is the best investment you can make and it can last for years if properly tied when on (to prevent flapping in the wind) and properly stored during the summer. Shrink wrapping is expensive, and not reusable.

That's about it. If you run your engine in salt water, you should have thoroughly flushed the cooling system prior to starting the winteriztion of the motor. The rest of us can put the motor to bed now and rest easy our pride and joy will continue to provide many years of enjoyment to come. Have I missed anything?

Now, about your bill...............

Happy boatin'

Dave Brown
Brown's Marina Ltd.


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Contact Information:
Brown's Marina Ltd.
1641 Chaffey's Lock Road
Elgin, Ontario, K0G 1E0 CANADA

Tel: 1-800-561-3137 (toll free)
Tel: 1-613-359-5466 - Fax: 1-613-359-6376
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