how to winterize a pontoon boat

How to Winterize a Pontoon Boat & De-Winterize (The Steps)

With the winter months just around the corner, it's time that you put your pontoon to rest for the season. That also means performing all of the necessary preparations to make sure your boat is protected from the cold while it's tucked away in storage.

Funny enough, there are services out there that actually offer to winterize your pontoon boat for you. And although that might seem convenient, you can get the job done for less without having to hire the extra help. Wondering how to winterize a pontoon boat? Here are all the tips.

Why Should You Winterize Your Pontoon Boat?

Why can't you just toss it in the garage, cover it up with a few tarps, and call it a day? Well, that might seem reasonable if winter lasted just a day or two. But extended periods of cold can cause serious damage to your boat.

Remember that there are various electronic and mechanical parts that make up your pontoon, and many of them are designed so that they work best in warm conditions. Then there are all of the fluids that won't only potentially harden, but might also go through chemical changes at certain temperatures. This can be detrimental to the integrity of the inner workings of your pontoon.

On top of all of that, failure to winterize your boat will be recognized by the dealer and manufacturer as deliberate negligence. That means that if anything happens to your boat while it's stored in cold temperatures, your warranty won't cover it.

Steps On Winterizing a Pontoon Boat

winterizing your pontoon boat

It's really no question that putting your boat in winter storage requires proper preparation. So if you're storing your pontoon, it would be a good idea to dedicate a whole weekend for the task. And if you're set on doing it yourself and forgoing the service of your local marina or dealership, then here are the steps to winterizing your pontoon boat:

1. Clean Your Pontoon Boat

The obvious first step would be to clean your boat. Leaving any nasty residue from past boat trips can invite all sorts of fungus, mold, and mildew to develop and thrive. If you cook and eat on your boat, then any food particles left behind can attract unwanted bugs and rodents looking for a place to stay for the winter. 

And then of course any marine life that has managed to cling to the exterior of your boat will stick with more gusto after they're allowed to sit there for an entire off-season.

a) Remove Items

Here are some things you'll want to remove from inside the boat before you get started on cleaning:

  • Electronics
  • Life jackets and other flotation devices
  • Depth finders
  • Music and audio equipment
  • Watersports equipment
  • Any loose items or gear

Aside from the fact that cold weather can easily damage many of these items, moisture also tends to build up inside these sorts of items. Taking them off of the boat, cleaning them, and storing them safely away from your pontoon should protect them from damage and mold and mildew development.

b) Vacuum & Clean Interior

Once all of those have been removed, you can get started on the actual cleaning. Use a vacuum to pick up any loose particles, dirt, and dust from all of your boats nooks and crannies. Make sure to get any and all food residue that could attract mice and other rodents and pests.

And then when everything has been vacuumed, you can clean the interiors with mild soap diluted in distilled water. If your boat seats are in peril of developing mildew stains while in storage, you can clean them with a solution of water and vinegar in equal parts.

c) Clean Exterior

When all of the interiors are cleaned, you can get started on the exterior. The hull of your boat must be cleared of any marine wildlife and vegetation. These things can harden like cement when left over the winter season, making them almost impossible to remove without damaging your tubes.

Not any old cleaner will do the job. So make sure you've got some boat hull and bottom cleaner for better results.

We recommend Star Brite Ez-On Ez-Off Boat Hull & Bottom Cleaner.

After everything's nice and clean, it's imperative that you leave your boat out in the sun to dry thoroughly. Any moisture left behind on your boat will just as easily turn into mold and mildew or even corrosion.

2. Winterize Your Engine

Before you start tinkering in the engine compartment, you might want to consult your owner's manual for specific instructions. The engine is a sensitive piece of machinery and needs particular care even during winterization. So it would be wise to do a little research and reading before you start touching the engine.

For the most part, you can expect to follow these steps for winterizing boat engines:

  • If you have an outboard motor, disconnect the battery. That's about it for an outboard boat.
  • If your boat uses an inboard motor, you should find instructions in the owner's manual on how to drain the engine block. All engines follow different methods for draining the engine block so see to it that you consult your manual.
  • To prevent corrosion, you're going to have to spray fogging oil into the carburetor. Remove the spark plugs, give a generous spritz of fogging oil through the spark plug holes, and put the spark plugs without reconnecting the wires. Fogging oil creates a barrier in your engine and keeps rust under control.
  • If you use fuel with ethanol, add a fuel stabilizer into the gas tank. Then fill the gas tank tank 3/4 of the way.
  • Drain the coolant from the engine and replace it with anti-freeze. It might not be a good idea to use antifreeze that's ethylene glycol based since it can release toxins into the water. Propylene glycol based antifreeze is non toxic and should be your pick.
  • Replace all of the oil filters on your engine and change your oil.
  • Finally, make sure you switch off all of your valves and seal exhaust ports to and from your engine.

3. Disconnect the Battery

Should you decide to remove the battery for the winter, the first important step would be to charge it. Then take the battery and store it somewhere you're sure temperatures won't reach freezing. Indoors would be good, or perhaps a heated garage or outhouse. It's also important that you recharge the battery throughout the winter.

Then again, if you think you'd be better off keeping it on board, disconnect the wires and reconnect to a trickle charger. In some cases, your bilge pump might need to keep working, and the trickle charger makes it possible for that to happen.

4. Secure the Cover

Of course, you could always just throw a tarp over that thing. But there are world's worth of benefits when you protect your investment interior with a quality pontoon cover that's intended for your boat. The tighter fit and the better material let you keep dust and dirt out of your battery and other important features, and help prevent opportunistic pests from getting in. 

Some covers also provide protection against cold, which is exactly what engines need to survive the season. If you're willing to go the extra distance, shrink wrap could be an option.

Before you place the boat cover, see to it that you lay down traps for pests you think might want to take advantage of your boat. Traps for mice and poison for ants are just a few suggestions. Some boat owners even use peppermint oil as a natural way to keep pests away. If you're worried about rodents, shrink wrapping is known to provide even better protection since shrink wrapped boats have fewer entry points for pests.

Then you can go ahead and secure the cover. On the interior and deck, prop up some posts to tent the cover up. This just makes sure that it doesn't sag down into the boat if in case any water or snow manages to form on the surface. See some of the best pontoon boat cover support systems here.

You can also store a dehumidifier underneath the cover to keep moisture at bay. Others routinely spray non toxic disinfectant spray under the cover.

5. Store Your Boat

With your boat fully winterized, it's time to store your boat inside your garage. If you're planning to keep it on a trailer, it's especially important that you set the trailer on blocks and remove the wheels. This just makes sure no one can hook their vehicle to your trailer and then drive away with your boat in tow. You can also lock the the tongue for added safety. Check out our guide on how to secure a boat trailer from theft for more details.

Remove any and all electronics from the interior that might be of value since these can be easy to steal in case opportunistic characters try to take what they can from your boat. You might also want to take a look at your insurance policy to find out what it covers.

Basic policies will only cover certain items on your boat like your engine and large pieces of equipment. Rarely will a basic coverage compensate you for small electronic devices. If you want to make sure you won't end up spending to restore lost accessories for your pontoon boat after the winter, then you should contact your insurance provider.

How to De-Winterize a Pontoon Boat

De-winterizing pontoon boats for spring time follows pretty much the same process as winterization, just backwards. Peel back the covers or shrink wrap and check your pontoon boat for any damage. Inspect for dents, nicks, and other cosmetic issues that might have happened while it was in storage. You might also want to check your cover for any holes or rips.

Hang the cover or shrink wrap out to dry and then fold it up for storage. It should have come with a cover duffel bag for when you don't need it. Then you can replace your battery (if you removed it) or connect it (for an outboard), reconnect all of the wires to the battery, the spark plug cables, and put back the fishing equipment, flotation devices, and all of your electronics.

You might also want to check if everything is working before you head back to the water.

In some cases, there might be mildew stains on your seats. You can clean those up with mildew stain remover for a cleaner, fresher look (check this cleaning guide out). If the rest of your boat looks a little stained or dusty, you can give the whole boat a quick clean before you head to the dock.

Once you arrive, start the engine. There should be no need to empty the fuel tank for the task if you filled up the fuel tank with fuel before storage.

Some boaters like to completely get rid of the propylene glycol based antifreeze in the system to protect the equipment before using the boat again during spring. Since the stuff is non-toxic, you can let it run into the waterway especially if your boat uses an open system to protect the engine from overheating.

What About Sticky Residue?

how much does it cost to winterize a pontoon boat

Even with a thorough cleaning, it's possible that you might find sticky gunk on your boat after storing it for the winter. You might also find patches of glue residue after removing decals and stickers from your boat before storing. If that's the case, then you might want to grab a bottle of glue or adhesive remover.

This stuff gets rid of all sorts of goo, glue, and adhesive to give your boat that ultra clean finish. Just spray it over your problem areas, leave it for a few minutes, and then wipe away the goo and residue to reveal the clean surface underneath.

We like using Goo Gone Adhesive Remover Spray Gel.

Frequently Asked Questions

Do you have to drain pontoons?

That really depends. Most pontoon boats are designed so that water doesn't get into the tubes. But if you have an older model, you can pull out the drain plugs at the bottom of the tubes to get rid of any water that might have accumulated during the season.

Make sure you leave the tubes without the cover to allow the residual moisture to evaporate. Some boat owners add in some alcohol to speed up the drying process. You can use all-purpose oil to loosen up the plugs if they're a little stubborn.

Can you leave a pontoon boat in the water for the winter?

It might be a lot easier, but the short answer would be no. Leaving your pontoon boat out on the water for the duration of the winter season until spring means exposing your boat to cold temperatures and snow, potentially damaging not only the exterior, but its engine, battery, bilge pump, fuel tank, and accessories as well. This also opens up the door for a variety of marine animals to cling to the bottom of your boat and wreak havoc.

And let's not forget - refusing to protect your investment also means that you might end up voiding your warranty or insurance. Deliberate negligence of your responsibility to care for your boat, especially during a perilous winter, could leave you unable to file for a claim to repair whatever damages happen during the cold season.

How much does it cost to winterize a pontoon boat?

Materials for winterization including fuel stabilizer, a brand new cover, new spark plugs, oil filters, fogging oil, engine antifreeze, and the rest should cost you no more than $150. If you're looking to get your boat winterized by a professional service, then you might be looking at a fee of $300 to $450. You can also get the job done by a private mechanic for just around $200 or less

Ready for the Winter

It might not be necessary to pay a service several hundreds for the task of winterizing your pontoon boat. Heck, if only more pontoon boat owners knew how to store a pontoon boat for the winter, then these services might very well be run out of business. But hey, if you're not keen on spending time doing it yourself, then outsourcing the task might be well worth the money.

However if you were looking to save up on expenses and were curious to find out how to winterize a pontoon boat by yourself, then these tips should help you with all the steps. Just make sure to go over everything twice to guarantee your boat's safety during storage.

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