Tips for Winterizing & Storing Your Pontoon Boat

Pontoon shrink wrapped for winter storage

Though many boaters are never quite ready to end to their season on the water, at some point we have to admit that winter is just around the corner. Winterizing your pontoon boat is an important part of overall maintenance that needs special attention. The process certainly isn’t as fun as spending a day at the lake. But taking the right steps will protect your investment and ensure your boat won’t encounter problems over the colder months and into the spring. To help you out, we’ve put together a guide on how to winterize your pontoon boat before storing it for the off-season.

Step 1: Clean Your Pontoon Boat

Clean out the Interior

Remove any equipment from the pontoon, such as fishing or water sports equipment, flotation devices, ladders, accessories – anything that’s not bolted down. Leaving these extra items on the boat while in storage creates a risk for mildew to form with any moisture that becomes trapped.  

You should also remove remove non-factory installed electronic equipment, such as external audio players, depth finders, or anything with batteries, and store these indoors to prevent damage or theft.

Give the floor and cushions a thorough cleaning, removing any dust, dirt, and food crumbs. Wipe everything down with a mild polish and let surfaces dry completely. This will reduce the chances of any mold or mildew growing in the interior of your boat and make your pontoon less inviting for any rodents looking for a place to call home during the winter.

You can leave a few mouse traps or poison out for prevention, but be sure to clean them up in the spring so any children or pets are not the first to find them. A non-toxic option is peppermint oil, which is a natural mouse repellent; mix a few drops with water in a spray bottle and spray the cracks and corners of the boat where rodents might make their nests.

Clean off the Exterior

After taking your pontoon boat out of the water, check the exterior for any plants or mussels attached to your boat, as they will be much easier to remove now than in the spring. Spray down the boat’s exterior and let it dry before putting a cover on. You can also apply a polish to the sides and beneath your pontoon boat to reduce the chances of any rusting and so your pontoon will look great when you unveil it in the spring.

Step 2: Winterize the Engine and Fuel Tank

Since your engine will be dormant for a span of months, you’ll want to make sure it’s properly protected. Be sure to consult your owner’s manual for specific instructions on preparing your engine for storage.

In cold temperatures, any lingering water in your pontoon boat’s engine will expand, resulting in cracking and damage. Once your boat is out of the water, you will likely need to drain all water and the coolant from your outboard or inboard engine and replace it with an antifreeze product that is propylene glycol based.

Lubricate the engine cylinders by spraying fogging oil into the carburetors and spark plug holes, following directions on the fogging oil package.

Finally, you’ll want to store the boat with a fuel tank that’s about 3/4 full. If the fuel has ethanol, add a fuel stabilizer to protect the fuel. This will prevent phase separation, which causes buildup at the fuel pickup over time, creating real problems if the engine if you start up the engine in this state.

Step 3: Charge and Store the Battery

If you plan on taking your pontoon boat out of the water, remove your battery and store it in a dry environment that’s close to room temperature, like your basement or storage closet. Make sure that the battery is fully charged before you store it away. You can take it to a marina, or sometimes an auto center, for them to test the battery and charge it up if necessary.

Step 4: Use the Right Winter Cover

Putting a tarp over your pontoon boat is better than having no cover at all, but there are many pontoon boat covers designed specifically for handling extreme temperature changes and lasting through a harsh winter. A good cover should be able to fit your boat snugly and should be able to expand and contract slightly to avoid ripping from temperature changes.

You’ll want to patch or repair any cracks or holes in the cover to prevent rodents from entering, and spray the cover with repellent to prevent chewing. Mice love to make nests in seat cushions on pontoon boats, which typically results in damaged cushions and a mess to clean up.

The biggest concern if your boat will be left out in the open is the potential for a pooling effect on the cover. If water collects on your cover, it can weigh down on the cover and damage it, or leak through to your pontoon boat. You want all moisture to slide right off, which is why many covers come with poles to prop up the cover. Throughout the winter, check to make sure there isn’t any pooling on your cover, and tend to it the best that you can if there is.

Another great option is to shrink wrap the pontoon. This ensures there is no space for water to pool or leak in, and you don’t have to worry about damage to the pontoon cover that you may use throughout the year. Shrink wrap kits can be purchased at marinas and online, but many pontoon boat owners choose to have a professional do it for them.

So there you have it! You’ve taken the necessary steps to protect your pontoon boat inside and out for storage over the winter. Now the countdown to next year’s boating season begins.

This article was originally posted on November 20, 2013. It has been updated with additional information on the winterizing process.