How to Winterize an Outboard Motor

By Peter11 mins read

Outboard motors/engines are classified into two categories: the two-stroke and the four-stroke.

The most fundamental is increased fuel consumption compared to a four-stroke engine. Four-stroke engines are more fuel-efficient but heavier. They also lack power in comparison to its smaller sibling. Whether you have a two or four-stroke outboard engine, maintenance is an important issue.

Almost all sailboat owners have a tender onboard either for safety or to take then on the beach. It is necessary since their boat’s deep keel will prevent them from getting too close to shore. They are well aware that sea salt and the fact that these engines do not operate continuously make them more vulnerable to damage. Hence, they will have to pay attention to their maintenance.

Because prevention is always more effective and cheaper than a repair, in this article, we will see checkpoints and practices that will drastically increase engine longevity and reliability.

If you do not take care of them regularly, it can cause damage that you cannot fix from one point onward.

Now let’s take a look at how you should winterize your small outboard engine:

Flushing

This process is so simple, and yet at the same time, very important for the longevity of the engine. That is because we remove the salts from the inside.

This process is also recommended by manufacturers, regardless of type, two-stroke or four-stroke, which works with an open cooling circuit.

The best ways to flush your engine are these three:

A special motor flusher muffs applied to the sides of the lower unit
A special hose socket located low on the lower unit
Or you can mount it on a barrel filled with freshwater.

Some manufacturers argue that you should flush your engine during operation, at low RPMs, and others with the engine off. It is advisable to consult your mechanic to guide you properly. You should always flush your engine when it is still warm. That way, the salts are easily detached from the inside.

Personally, I let the motor run until the water output is a little warm.

Cleaning

It is advisable to open the lid of the engine and clean all mechanical parts.

It is also important to thoroughly clean the lower part, that is where oils, dirt, and salts can be found from the continuous operation of your engine. Finally, a good freshwater rinse before closing, without the fear of short-circuiting the various cables, since they are constructively protected from the water inlet.

Give the engine a good wash with soap and freshwater. Make sure to scrub too.

You can also spray some rust preventive spray in all the mechanical parts like the intake, the outside of the carburetor. That way, you protect the engine from any corrosion and moisture during the winter. You can use any penetrating lubricant like WD-40 or Lloyds.

Impeller

This is the mechanical part responsible for properly cooling the engine. We should, therefore, check the blades, and any deformations should be reported to a mechanic. In any case, the impeller is checked during the annual inspection. But this should not reassure us, because, after cruising in shallow waters, sucking sand would cause damage to the impeller.

Fogging

When the engine runs out of fuel, spray the fogging oil straight into the carburetor. The fogging spray is an anticorrosive oil that will shield the interior surfaces of the carburetor and the cylinders. Typically the engine will run a little rough moments before it runs out of fuel. As that happens, give the carburetor a substantial shot of fogging oil and make sure that you spay a full coat to all inner surfaces.

Oil Change

You should extract the oil from the engine and replace it with new. Make sure to put the proper amount of oil in it. Every make and model is different, so check the manufacturer’s specifications, so you don’t underfill or overfill it. For most outboard motors you can use a standard 10W-30 marine engine oil.

You should also change the oil filter. Always make sure that when you change the oil filter that the old gasket comes off and you don’t double gasket because it will start leaking. Those are similar to car oil filters, and many people make this mistake when changing the filters on their cars.

Drain the gear oil by taking the bottom plug and unscrewing the top crew. What you want to see here is a slightly cloudy oil coming out. Check it is like milk or cream. If it is like that, you will need to replace the gaskets because water got in mixing with the oil and caused it to change to that color. Replace the gear oil with regular 80W-90 oil.

If your engine has a fuel filter, you should replace it every couple of years.

Grease

You should grease all your grease points with a good marine grease. There are many spots that you should apply the grease on, so take your time not to miss any.

Propeller

Remove the propeller so you can check the shaft for anything wrapped around it like fishing line. Obviously, if this is the case, you need to remove it before it cuts through the prop-shaft seal and allows water into the gearcase.

If the prop-shaft seal is already damaged, it would be best to get it fixed over the winter when business is slow at the repair shop. The last step: spread some grease over that exposed shaft, so it doesn’t rust over the winter.

Waxing

This is the last step of the “How to Winterize an Outboard Engine” guide. Before putting the motor away, simply apply a fresh coat of wax on the outside of the engine. This will help your outboard engine looking like new for years to come.

Storing

I have seen many motors covering the engine during off-season, so make sure you are not one of them.

When you cover an outboard in plastic, you ensure that any moisture that’s under there cannot escape through the vents. This moisture can start corroding the electrical connections and moving parts like the throttle linkage.

Also, you should always store your outboard engine upright. They are designed to sit that way so they can drain properly. Storing the engine laying down risks water draining where it shouldn’t.