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How to Perform Your Own Boat Oil Change

A boat on a trailer.

If you own a vehicle, you know regular oil changes are vital to vehicle maintenance and extending your engine’s life. Boat engines are no exception. Performing a boat oil change is similar to doing so for a road vehicle, but there are a few differences to keep in mind.

Why Changing Your Boat’s Oil Is Important

How to Perform Your Own Boat Oil ChangeIn any engine, used oil collects contaminants from the combustion process, and particulate matter builds up as a result of friction between moving metal components. Failing to change oil can slowly damage the engine if particles of debris make their way into small clearances and grind away at precisely calibrated engine components.

In addition, unlike cars, boats usually don’t run year-round. For those that are stored in the off-season, having contaminated oil sitting in the crankcase for months can lead to corrosion and premature wearing of components.

With the exception of the breaking-in period for new engines, gasoline engines on boats should have their oil changed every 100 hours or so of run time, which probably translates to once annually for non-commercial users. Check your owner’s manual to determine the exact service interval for your engine.

Out With the Old

Gather a new filter, fresh oil, a drip pan, clean rags, a filter wrench, a socket set, gloves and a funnel. Run the engine for a few minutes to stir up any contaminants from the bottom and make the oil easier to drain. If your engine requires it, be sure to have water running through it for cooling purposes. Once you’ve run the engine for a bit, turn it off.

If you have an outboard engine, start with the engine in the upright position or you’ll get a huge mess upon removing the drain plug. Place the pan and a few rags beneath the propeller. Next, you’ll need to make a choice: a quick and easy method is to use an extractor pump and suck the oil out through either the drain plug or the dipstick tube. For inboard engines an extractor pump may be the only option due to lack of clearance underneath the engine. There are also kits available consisting of a hose and fitting that will attach to the drain. If you go this route, attach the hose to the drain with the bottom leading to the pan, and then slowly tilt the engine down until oil flows into the pan.

Once the oil is drained, reposition the engine upright, remove the hose and replace the plug, taking care not to cross-thread it. Next, remove the oil filter, and be ready with rags underneath and a leak-proof container to store it. Take a clean rag and wipe the housing down, making sure there is no gasket left behind, as that could cause a poor seal against the filter’s gasket and lead to leaks.

In With the New

Rub a light layer of oil on the rubber gasket of the new filter, and place it on the engine, tightening only by hand. Again, be careful not to cross the threads.

With the drain plug tight in place, open the oil fill cap, refill with as much new oil as the owner’s manual specifies, and replace the cap. Next, start the engine up and allow it to run for about a minute. Listen for any unusual sounds and check for leaks. If there are none, turn it back off, check the dipstick to confirm that the level is right, and top it off if necessary.

Use the rags to make sure any drips or small spills are cleaned so they don’t make their way into the water, even if they’re on board. Make sure to properly dispose of all used oil.

Performing a boat oil change isn’t a terrible job if you’re prepared, and it’s important to do. If you have any questions at all, remember that you can consult your owner’s manual for specifics about the procedure, intervals and materials.

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 performing a boat oil change, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photos courtesy of Flickr.

Blair Lampe View All

Blair Lampe is a New York-based professional mechanic, blogger, theater technician, and speechwriter.  In her downtime she enjoys backpacking wherever her boots will carry her, rock climbing, experimental theatre, a crisp rosé , and showering love on her 2001 Sierra truck.

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