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Can I Use Sea Foam in My Boat?

A speedboat on the water

Boats at dockThe season is changing and warm weather is on the way. And for a lot of us, that means it’s time for our other favorite motorized vehicle — a boat. Many car maintenance tips and tricks carry over to the marine side. So what about Sea Foam?

In case you don’t use this product on your land vehicles already, it’s a popular engine treatment. It cleans and lubricates critical parts like the fuel injector and carburetor passageways, the intake valve and chamber, and the upper cylinders. It also works in your crankcase oil to break up and liquefy harmful deposits that could clog your engine. And it stabilizes gasoline and diesel for up to two years. It’s the Swiss Army knife of engine chemicals.

Do They Make Sea Foam for Boats?

No, but that’s because one size fits all, and the regular formulation still works. Your marine engine — outboard or inboard, gasoline or diesel — has more in common with your car engine than you might think. It works just the same, so pour some of the product into the fuel tank and crankcase (following the label instructions carefully), and you’ll get the same benefits.

What About The Environment?

Sea Foam is made from petroleum ingredients, so the usual rules about disposal and spillage apply (and can vary from state to state or even city to city, so always check to be sure). Also, if you’re doing this maintenance on a boat that’s already in the water instead of in storage, check with the harbormaster or other authorities about any environmental regulations governing boat maintenance and petroleum products.

Maintaining Other Parts of Your Boat

While you’re at it, take the time to thoroughly inspect your boat for any issues you may have missed last year or that crept up during the winter. Corroded parts that touch the water can lead to the failure of essential systems. Check, and if necessary, replace them. Inspect your propeller for damage, look for loose connections within the engine and steering systems, and be on the lookout for other deficiencies that could lead to anything from a choppy ride to the prop falling off. Give the electrical systems and seals a good inspection as well. Make sure the bilge pump is in good working order.

And treat your Sea Foam application like you would an oil and filter change for your car. Whenever you apply it, train yourself to check your fluid levels and examine the fuel lines, oil lines, plugs and hoses for signs of wear, replacing them if necessary.

All of these maintenance steps are important — and a bottle of Sea Foam can make a great start.

Check out all the oils, chemicals and fluids available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on using Sea Foam, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photos courtesy of Wikimedia Commons.

Mike Hagerty View All

Mike Hagerty is an automotive journalist whose work has been featured on radio, TV, in print and online since 1997. He's the Publisher and Editor of, and contributes car reviews to the Los Altos Town Crier and Previous outlets have included KFBK and in Sacramento, California, the ABC television affiliates and Hearst-Argyle and Emmis radio stations in Phoenix, Arizona; AAA magazines for Arizona, Oklahoma, Northwest Ohio, South Dakota and the Mountain West and

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