How To Summerize A Boat!


There is nothing more important in boat ownership than properly taking care of your boat! Boat’s are not cheap, and they are extremely finicky, so when it comes to storing the boat through the summer when it isn’t boating season, or you will not be around. The engine will need to be summerized!

How To Summerize A Boat?

  1. Check the Lower Unit oil for water. Reseal and replace the gear lube if you find water.
  2. Flush & Fog the Engine.
  3. Drain the Engine’s VST or Carburetors.
  4. Turn off Battery Switches, or disconnect the ground lead from the battery but leave the bilge pump float switch hooked up.
  5. Remove or cover all of the boats cushions.
  6. Cover all electronic screens and gauges.
  7. Leave the Engine in the tilted down position.

Summerizing a boat is a simple process that almost anybody can perform. It is a cruicial part in preserving the engines life and minimizing the head aches of pulling a boat out of storage!

What Is Summerizing?

Locations play a huge part in the types of boats, the water ways, the activites, and many things that go on in the marine industry.

Even how the boat is stored. Summerizing a boat or an outboard or inboard motor is the process in which the engine is stored.

Whenever a boat is put away for a season, there are certain things that need to be done in order to make it an easy process to get the boat back in service next season.

For Northerners, boats and engines are winterized before winter storage. Down here in the South, boats and engines are summerized for summer storage!

A lot of people think that if the weather is nice, then people should be boating all year round! I completely agree with them.

Boats are summerized because of travelers and seasonal crowds. For the most part in states like Florida and other coastal areas where people have vacation homes and get aways. They will keep a boat and then summerize it before returning to their summer home.

Somewhere up North where the weather is warm again. Then get the boat back out when the fall and winter comes back around and they return to their second home.

Most of the time these people are referred to as “snow birds!” Which we really, truly do love!

What’s The Difference Between Summerizing & Winterizing?

Summerizing is different from winterizing because of the different things that are needed to be prevented.

Winterizing is a general term but is normally thought of when talking about freezing temperatures. There are a lot of different things that need to be thought about when we are talking about freezing conditions.

Water inside of the block and hoses in the boat. You don’t want that water freezing and busting any of the engine’s components or the hoses to your washdown or livewell pumps.

It’s also important to think about the batteries and the affects of freezing weather. We’ve written another article that talks all about batteries and storing them during the winter here.

Summerizing on the other hand has to mainly deal with prepping and storing an engine for the summer, in warmer conditions.

Where the cold won’t be affecting it.

What’s The Difference Between Summerizing & De-Winterizing?

Then there is also the De-Winterizing. This is taking care of all the things that need to be done when getting the boat ready for the summer.

After a long winter when the snow and ice is starting to melt. It’s time to get the boat back out and ready to go. Undoing all of the cushions and covers.

Removing the shrink wrap and maybe even trying to save it for next season! Here’s how you can save that shrink wrap or dispose of it properly.

Where as the summerizing process for storage, is all about decomissioning the boat for the season.

This gets into semantics just a little bit though. Depending on where you live, there are a lot of people that call de-winterizing, summerizing.

So, I wouldn’t get to carried away with being politically correct on de-winterizing vs. summerizing.

Depending on your location, most people will know what you are talking about or what you mean!

Fuel Care Prior To Summerizing

The first step in beginning the summerizing process is to treat the fuel. This starts by making sure you fill up with the correct fuel.

It is always recommended that we run REC 90 or non-ethanol fuel in any boat. Sometimes this isn’t possible, but here is a solid break down of why it is important not to run ethanol-blended fuel in your boat.

So you want to make sure you fill up your last fill up with REC 90 fuel and add your stabilizer when you are filling up the tank. This helps to get that mixing process started.

I see it a lot of times where someone wants to store their boat. Then they take their boat to where it is going to be stored, and once the boat is set where it is going to live, they add the fuel stabilizer in!

Which, doesn’t do anything for all of the fuel that is in the fuel lines and the engine.

It’s so extremely important to go out and run the boat again before storing it. This will get the sabilizer mixed in really well with the fuel and then get all of that treated fuel through the fuel lines and into the engine’s fuel system.

Checking The Lower Unit

Then after the fuel is treated and set up. It’s always best to take the next step and check the condition of the gear lube in the lower unit.

If the lower unit has a leak and is filled up with milky oil or water. The last thing you want to do is store the boat in this condition.

That milky oil will eventually separate, and then you are left with water in the gear case. That water will begin to rust the bearings and the gears. Weakening them!

Which is just a formula for disaster when the engine is put under a load.

Checking the condition will let you know if you can just store the boat as is, or if you need to change out the gear lube.

Possibly even pull the lower unit and fix the leak or wait until next season to make the repair.

Either way, you don’t want that lower unit stored for eight months full of water. That will just turn into a nightmare like a lower unit failure, costing some serious cash.

Flushing & Fogging The Engine

This is the process of the summerizing job that most people are unsure of. It is actually a really simple process, but you don’t know it is, until you have performed it!

A flush and fog are exactly that. Flushing the engine with fresh water and fogging it to oil up all of the internal components of the engine.

For the flushing part, you just need to hook up the engine to a set of earmuffs on the lower unit so that the engine stays cool and the water pump stays wet.

We’ll take off the air intake, a hose, or a sensor that allows us to get access to the air intake or throttle body of the engine.

Simply start the engine and raise the RPM to about a 1,000 or so and begin spraying fogging oil into the throttle body. The engine will bog down, but we want to continue spraying the oil in until the motor has a thick cloud of smoke coming from the exhaust.

With a 2-Stroke engine, it is pretty common to change the spark plugs after the engine has been started next season. Due to the fouling of the plugs and that all 2-Strokes love a set of new plugs!

Once you see that thick cloud of smoke, quickly turn the key off, and that’s it!

Draining The Engine Fuel System Components

After the motor has been flushed and fogged. You don’t want to let the fuel sit in the carb bowls or the VST.

The fuel can become gummy and varnish the inside of the tank. It isn’t as bad in the fuel tank because it is not a small concentrated area like it is in the VST.

So we want to drain the fuel out of the engine before closing it up. Most VST’s and Carb’s have little drain screws on the bottom so that they can be drained.

Just unscrew the drain and pour the fuel into a glass or plastic clear jar so that you can inspect the fuel and see what kind of quality it is.

This will be that last thing that needs to be done as far as the engine is concerned.

Battery Care

We don’t want to forget about the other things that are in the boat. One of the bigger items are the batteries.

We all know that boat batteries are anything but cheap! So it’s important to make sure that the battery switches get turned off and that there isn’t any draw on the batteries.

You can even go to the extent of removing the grounds from the battery to completely disconnect them.

Just be mindful of making sure that the boat’s bilge pump float switch stays hooked up and operating properly.

The last thing we want is for some kind of junk to plug up the drain hole and fill the boat up with water if the bilge pump and float aren’t working!

It isn’t a bad idea to have a charger on the batteries with the ability to hook them up and charge them periodically throughout the off season. It isn’t recommended to leave the batteries on the charger for the entire season with the charger putting out 12VDC to them all the time.

A trickle charger isn’t that bad though if you have one of those.

If you would like more information on batteries and how to care and maintain them. You can read this article here that we wrote on them!

Finishing With The Boat

Now the next thing to do is to make sure that the boat is taken care of.

We are talking about covering up your cushions, or removing them and putting them in the cabin. Keeping them out of the sun which can damage them and take the life right out of them!

This goes for all of the electronics and screens that are on the boat too. Covering up the gauges, the VHF radio, the stereo, and the GPS’s. Anything that can get a sunspot or get damage to the LCD screen needs to be covered.

If this is starting to sound like a lot. Then there is always having cover’s made for the boat. Canvas covers that snap in place is a great way to make storing and protecting the boat extremely convenient.

Then if having cover’s made is a little much. There is always shrink wrap! Which can be reused a couple of times if properly installed. Here is that shrink wrap article from earlier.

Storing The Boat

The only thing left to do is to store the boat! The best place to store a boat is inside or in the shade. Of course, that is a luxury that very few of us have!

So just finding a nice safe place to store the boat is what we are really looking for.

If the boat is being stored on a trailer. It’s not a bad idea to protect the trailer wheels from the sun and to make sure it is chalked correctly.

It’s also important that the engine is stored trimmed in the down position so that the trim seals are protected from the sun. We have some more information on storing the boat here where we talk about what’s the best position to store the engine in.

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Hopefully, this helps you get a better understanding about summerizing a boat for the summer!

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Aaron Hilligoss

Aaron has been working in the Marine Industry for over a decade and holds certifications for Yamaha and Mercury Marine. It is not uncommon for him to own and be working on at least three different boats at any given point in time!

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