Storing your boat for winter? Our comprehensive winterising service avoids corrosion, protects your warranty, and prepares your outboard for storage. 

Providing expert outboard motor servicing and repairs for over 50 years, you can rely on MB Marine to thoroughly prepare your outboard for winter. 

Avoid corrosion and large repair bill next spring by investing in professional winterisation by your trusted local outboard expert.

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    50+ years of industry experience

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    Workshop based conveniently in Southampton

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    Mobile winterising service also offered



Poor maintenance can often do more damage to an outboard motor than high usage can. So during the winter and off-season, it is important that the maintenance of your outboard isn’t neglected. As well as ensuring that your outboard is kept up to date with servicing, it is vital to ensure that it is also properly winterised. Failure to properly winterise an outboard motor can result in serious and possibly even terminal damage to it.

Whilst some people may try and undertake the winterising process themselves, unless you are highly skilled and knowledgeable in the area, we would always recommend that you use an approved outboard service centre, such as MB Marine, to carry out the work for you. This is especially important if your outboard motor is still under warranty, as failure to properly maintain and service your outboard as per the manufacturer’s guidelines, can invalidate your warranty.


Winterising is the process of getting an outboard motor ready to be put away in storage for the winter. The winterising process covers a number of key procedures, that if not carried out before being put into storage, can cause the motor to corrode, seize and ultimately land you with a large repair bill.

For more information about our Winterising service, call us on 02380 388 608 or email sales@mbmarine.co.uk.


Flushing the Engine - Saltwater can be highly corrosive to metal, so to avoid internal corrosion of the engine’s aluminium waterways, it is vital that outboards are properly flushed with clean water before they are put into storage.

Treating the Fuel - Fuel does not store well in engines and can lead to corrosion, so it shouldn’t be left untreated in the tank over winter. Part of the winterising process is to add a stabilizer to the fuel.

Inhibiting the Engine - In order to protect the inside of the engine whilst it is in storage, it is important to add a coating of fogging oil to bores. This will coat the inside of the engine in a protective film, protecting parts such as the big ends, cylinders and valves.

Applying Corrosion Guard to Engine - Corrosion Guard spray is applied to the engine’s metal and painted surfaces, to help prevent rust and corrosion from forming. It will also be applied to any existing patches of rust or corrosion to prevent them from worsening.

Outboard Motor Winterising Service
Outboard Motor Winterising

Draining the Engine Cooling System - To avoid the risk of damage being caused by water freezing and expanding in the motor whilst it is in storage during cold weather, it is thoroughly drained of water.

Checking and Replacing the Spark Plugs - Spark plugs are checked both for their condition and the electrode gap and are replaced if necessary.

Checking and Replacing the Engine Oil - Engine oil deteriorates over time as it absorbs moisture and gets contaminated, so checking the oil is part of the winterising process.

Checking and Replacing the Gear Oil - As with engine oil, gear oil can also deteriorate in quality, so this will also be checked and replaced at the same time. We always use proprietary outboard oils to ensure they contain the correct additives for use in water.

Greasing Moving Parts - It is vital to apply water-resistant grease to all moving parts of the outboard before placing it in storage. This includes the propeller shaft, joints, cable ends, nuts and bolts and other grease points prone to seizing.

Sean Nagle
Sean Nagle
Mark's a very helpful guy who go the part I needed in two days from Holland - no mean feat in these Brexit days...! Recommend him and MB Marine
George Thompson
George Thompson
We used MB Marine Sales to check over our boat to get her ready to be sold, as well as winterising the engines. There was clear communication throughout, really helpful and professional. Can’t recommend Mark and his services enough.
Darren Botting
Darren Botting
Mark knows his stuff absolutely a top bloke bought several parts from him for my mercury 15 hp 2 stroke and decided to purchase an hour old mercury 4 stroke just waiting for Mark to fit if you want your engine s serviced mark is the man 5 * service
Andy Andy Murray
Andy Andy Murray
Mark and Craig are 1st class. Ive used MB marine to service and maintain my ribs since I bought them. Nothing is too much, really helpful and always on the end of the phone to help.
Matthew Holland
Matthew Holland
Mark has been an absolute life saver, provided the parts we needed to fix the impella on my Rib. He was really busy but then proceeded to spend lots of time on numerous calls helping us out with telephone support which was invaluable! I have never experienced service like this and someone who will go the extra mile to help! I recommend everyone puts a MB Marine sticker on their engine for when you need him, you won’t find better!
Tim Lees
Tim Lees
Absolutely fantastic help and service this morning especially considering the difficult covid restrictions. So very impressed with the positive and helpful attitude and advice We will definitely be going back in future when we need repairs service or anything else Also so very glad you are now supporting and servicing the Lymington area Will most highly recommend Thankyou
AquaMarine Yacht Repairs & Refits
AquaMarine Yacht Repairs & Refits
We have been using MB Marine for a numbers of years now, very reliable and a professional set up workshop for outboards for repairs and servicing, always been there when we needed them and with realistic prices.
Portsmouth RIB Charter
Portsmouth RIB Charter
Excellent service as always - have been using Mark to service and repair both my outboards since I bought both ribs. Great and reliable work every time! We use both our ribs as commercial charter boats so always need them in perfect working order - they have never let us down with care and maintenance that Mark provides. Would highly recommend.
Elev8 Fitness
Elev8 Fitness
Fantastic service - very knowledgeable and was able to diagnose the issue with my engine. Would recommend 100%
August Race Greece
August Race Greece
I have always used MB Marine for all our boats servicing and repairs. Friendly efficient service from everyone there. Would highly recommend!

FAQs Frequently asked questions relating to outboard motor winterising

What will happen if I leave water in my outboard motor?

If you leave water in your outboard motor for any length of time when it is not being used, you run the risk of severe and very costly damage. As temperatures plummet during the winter, any water that has been left inside the motor will freeze and expand, causing cracks and other damage to occur internally. Additionally, salt water is corrosive and can cause corrosion within the engine.

Do both 2 stroke and 4 stroke outboard motors need to be winterised?

Yes. While the exact process varies slightly, all outboard motors, both 2 stroke and 4 stroke, should be winterised to prevent damage.

Do I need to winterise my outboard motor, even if it is going to be stored indoors over the winter?

Yes. Whilst some of the winterisation process is to prevent damage caused by freezing temperatures, other aspects of the process, such as replacing oils, treating fuel and greasing moving parts should be carried out if an outboard motor isn’t going to be used for a long period of time, regardless of the temperature.

When should I winterise my outboard motor?

You should winterise your outboard motor as soon as the temperature drops sufficiently that there is a risk of frost and you have finished using your boat for the season. In the UK, this is usually around the end of September.

When should I de-winterise my outboard motor?

It is safe to de-winterise your outboard motor as soon as the last of the spring frost has passed. In the UK, this is usually around April.

Does a outboard motor need to be winterized?

Yes. An outboard motor typically needs to be winterized if it will not be used during the colder months. Winterizing helps protect the motor from damage that can result from freezing temperatures and the potential for ice formation.

How do you winterize an outboard?

Winterizing an outboard motor involves key steps such as cleaning, flushing the cooling system, changing engine oil, adding fuel stabiliser, replacing gearcase lubricant, and fogging the engine. Treating the spark plugs, greasing fittings, disconnecting the battery, storing the motor upright, and covering it in a dry area are also essential. Adhering to manufacturer recommendations, consulting the owner's manual, and seeking professional assistance when in doubt ensures a thorough winterization process.



What to do to winterize a 4 stroke outboard?

Winterizing a 4 stroke outboard engine is crucial to prevent damage during colder months. Steps include flushing the cooling system, changing oil and oil filter, treating the fuel system, and storing the outboard in a dry and secure location. Proper winterization ensures the engine is ready for use when the weather gets warmer.



When should you winterize your outboard motor?

Generally, it is recommended to winterize your outboard motor before the temperatures drop below freezing. This is typically done in late autumn or the early winter months. By winterizing your outboard motor, you can prevent any damage caused by freezing temperatures, such as cracked engine blocks or water pump failures. It is important to follow the manufacturer's guidelines and consult with a professional if you are unsure about the specific timing and steps for winterizing your outboard motor.


Does a 4 stroke outboard motor need to be winterized?

Yes. A 4-stroke outboard motor should be winterized to protect it from potential cold weather-related damage. Winterization involves steps such as cleaning, flushing the cooling system, changing the oil and filter, adding fuel stabiliser, and protecting the engine with fogging oil. Proper winterization helps prevent issues like freezing and corrosion, extending the motor's lifespan and ensuring it's ready for use when the warmer seasons return.


What happens if you don't winterize 4 stroke outboard?

Failing to winterize your 4-stroke outboard motor can lead to several potential issues. During colder months, water left in the engine's cooling system can freeze, causing damage to critical components. Additionally, without winterization, fuel can deteriorate and lead to carburetor or fuel injector problems. Corrosion can develop in the engine and its components, potentially causing long-term damage. Neglecting winterization may result in costly repairs and reduced engine lifespan. To avoid these problems, it's essential to properly winterize a 4-stroke outboard motor when not in use during the winter months.