Boating Basics Online is reader-supported. When you buy via our links, we may earn a commission at no cost to you. Learn more

How Often Should You Check the Engine Oil Level? (Things to Know)

Written by J. Harvey / Fact checked by S. Numbers

how often should you check the engine oil level

Checking on the engine oil is a common practice that people do not just for cars. We need to do this for our boat motor as well. But how often should you check the engine oil level of your boat? What considerations should we take into consideration?

In this article, we’ll take a closer look at when you should check the engine oil level and what it is that we need to check aside from the oil level. We’ll cover some basic things we need to know about oil too.

Keep reading to learn more.

When Should You Check the Engine Oil Level

Engine oil ensures that our boat engines work properly and efficiently aside from its protection. Thus, we need to make sure that the oil can do its job. One way to ensure this is to check that the proper oil level is maintained. But how often should you check your oil?

The engine oil level should be checked every time we set out on the boat, specifically before engine operation. By doing so, we can be certain that the oil helps the engine perform at its best.

During an engine oil check, make sure that the level is above the halfway mark but below full. When the oil is at the proper level, it will be able to lubricate and coat the inner engine components as designed properly. With that, it provides the protection that your boat motor needs.

All About Engine Oil


Before everything else, let’s take a short overview of engine oil. Engine oil or motor oil is a lubricant used for engines to keep the moving parts performing efficiently. It reduces friction inside the engine, which also helps in cooling and keeping the engine clean.

Aside from lubricating and protecting the engine, modern motor oils are also designed to do other things including but not limited to: reducing wear on engine parts, improving fuel efficiency, protecting emission systems, temperature protection, and even actually cleaning the internal engine.

Engine oils are made of base oil which comprises up to over 90% of the mixture, and additives that give the motor oil its viscosity and perform its other functions.

Oil may vary based on viscosity, and a different one may be needed depending on the situation. This leads us to two types of motor oil based on viscosity; the single-viscosity oil and the multi-viscosity type.

Depending on the operating temperature, motor oil needs to have a different viscosity to work effectively. It means that you may need a different type of motor oil for winter and summer. This is where multi-viscosity oil comes in as these adapt to varying temperatures making them useful if you operate your engine in varying temperatures.

Marine Motor Oil


Different engines need motor oil to work efficiently, especially when used for longer periods. However, the motor oil needs of boats differ from those of cars due to the marine environment where boats operate.

Here is where marine motor oils differ from those used in other engines. They are designed for use in a marine environment and are rigorously tested in such conditions.

The most reliable way to choose a good product is to look for motor oil endorsed by the National Marine Manufacturers Association (NMMA), which oversees marine oil testing. Their TC-W3, FC-W, and FC-W(CAT) tags are issued only to oil products that meet the stringent marine testing specified by the NMMA.

Marine motor oils are still similar to other motor oils, but they are tweaked in a few ways. One main difference is the focus on rust protection to improve engine performance in an environment with high moisture. Another difference is the ideal temperatures that they work with, which are geared for boating.

What Happens When the Engine Oil Level Is Not Right

As mentioned above, viscosity is an important aspect of engine oils. By having proper flow, the engine oil will work as designed. If there is too little oil, it will not be enough to keep the engine running smoothly. If there is too much oil, it may hamper the engine and create various problems.

Always ensure the proper oil level for optimum performance. This will also help extend the life of your engine.

When an Oil Change Is Necessary

Checking the oil level in the boat engine is important, but this is not the only thing we need to look out for.

We also need to check the oil’s color. Whitish color, what others would call milky, is a sign that water is mixing into the oil. In such a situation, it is time to get an oil change.

Suppose the oil is mixed with water, other than having the incorrect viscosity that promotes the necessary flow to keep engine operation smooth. In that case, it may also contribute to rust formation. Such a problem may also be due to the engine issue, so it’s a good idea to get the engine checked at the same time.

Many boat engine manufacturers recommend getting the oil changed for every 100 hours of use. Even if the oil is not milky, it’s a good idea to consider an oil change after that 100-hour mark, if not exactly at this point. A damaged engine will always be more troublesome and costly compared to getting a prompt oil change.


How often should you check the engine oil level? Now you know the answer to this question, including what to look out for. The boat engine is a reliable partner that we need to take good care of, and taking the time to check the engine oil level boat standards is one of the critical measures we should keep in our pre-boating routine.

If you have any comments regarding this topic or experiences you’d like to share, please feel free to leave them below. We look forward to hearing from you.

5/5 - (3 votes)