3 Critical Tips for Outboard Maintenance

Published on October 21, 2021

Simple but critical outboard maintenance tips will help make sure your engine stays in the best possible shape

How to care for outboard boat engines is important to understand, even if you’re not the DIY type. The fact is that the most basic forms of outboard boat engine maintenance are incredibly easy to perform, and yet will have a huge impact on your outboard’s reliability and longevity. 

So, just as you make sure your automobile gets basic maintenance on a regular basis, be sure your boat receives the same attention. 

1) Flush Your Outboard with Freshwater After Every Use

The cooling system inside an outboard depends on having a flow of clean water, and the best way to keep its internal passages and water pump clear is to give your outboard a freshwater flush every time you use it. While this is most critical for boats used in saltwater, those who do their boating in freshwater lakes and rivers aren’t off the hook as particulate matter and minerals are present there as well. 

The good news? Flushing your outboard is quick and easy. Simply attach the freshwater supply using the manufacturer’s recommended method, and let the water flow for 10 minutes or so. If you own a Sea Ray with an outboard, chances are there’s a Mercury engine on the transom. And that means flushing the outboard just became even easier — Mercury has this Flushing an Outboard Motor video that will walk you through the process.

2) Wash and Wax Your Outboard Regularly

Basic automobile detailing and fiberglass boat maintenance are similar in that both begin with washing and waxing; outboard boat engines also benefit from this simple measure. Most boaters will want to keep their engine cowls in good shape because they take pride in every detail of appearance, but beyond that, how your outboard looks will have a major impact on your boat’s resale value. Potential buyers will likely determine how well your boat was maintained at first glance, and an outboard that looks weathered and neglected won’t make a great impression. Keeping it washed will keep it shiny, and giving it a coat of wax at the beginning and end of every season will protect that gleaming finish.

3) Have the Oil Changed According to the Maintenance Schedule

Whether you do the job yourself or take your boat to your dealer or service center, it’s critical to have the outboard engine’s oil changed at the scheduled maintenance intervals. While you might guess it’s just as important as it is for a car’s engine, it’s actually even more important. Automotive engines operate at much lower RPM than outboards and only hit peak speeds for short bursts of time. But outboards often run for hours on end at high RPM, requiring higher oil viscosity levels — which can be lost over time. On top of that, unlike your automobile your outboard has a second reservoir of oil in the lower unit and it needs regular changing, too.

Changing the powerhead and lower unit oil in an outboard is a fairly easy process. While the specifics vary a bit from model to model, in all cases you’ll need to drain the old oil (and dispose of it properly), and fill the reservoir with fresh oil. In the case of the powerhead, you’ll also need to change the oil filter (lower units don’t commonly have oil filters). 

Your owner’s manual will show you how. But be forewarned, this is often a messy job, and while those who enjoy DIY outboard engine maintenance might not mind getting their hands dirty, the average boater leaves this task to the professionals. The important thing is just that you make sure the change takes place — whoever does it — in a timely fashion.

Boats and engines are mechanical items, and any mechanical item can need fixing from time to time. But taking care of these three simple outboard boat engine maintenance tasks will vastly increase the chances your boat will look and run great every time you’re underway. 

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