What Is Tilt Trim On A Boat? What’s The Difference?


Power tilt and trim, are you using the trim when you run your boat? Are you trimming up, do you tilt your engine up out of the water, do you tilt it when you trailer it? Have you wondered what’s the difference?

What is Tilt Trim On A Boat? The difference between tilt and trim on a boat is referencing the location of the outboard or the drive of the inboard. Trimming is used when underway and goes about 20 degrees of the way up and tilting is coming all the way up for storage.

Did you know there are ways to use your trim to improve your fuel economy? Here is how and everything that you need to know about tilt and trim on a boat!

The Difference Between Tilt & Trim

Yes, tilt and trim are both in the same component on the engine, but they have different functions. The tilting portion of the operation has to do more with trailering or getting the outboard out of the water.

(Especially for long term storage while the boat is in the water. Here is some more in-depth information on long term engine storage.)

While trimming on the other hand. It only has to do with only a short distance of movement and while the boat is underway.

On most manufacturers, the trim system has two separate stages. One for trimming and one for tilting. The trimming stage will be working until the engine reaches about 20 degrees of the way up.

Then after that, it uses the tilting portion until the engine is tilted all the way.

When trimming the engine while underway, this will improve the fuel economy of the engine and lighten the load.

That is because when the engine is tilted all the way down. The angle and force coming off of the propeller will push the bow of the boat down into the water.

With a little bit of trim, the engine will come up and the force and angle of the propeller will be pushing down into the water. Which pushes the bow of the boat up out of the water.

When there is less of the boat in the water and the bow is pointing slightly upward. It takes away a lot of the drag between the boat and the water.

Allowing the engine to work less, thus burning less fuel and saving you at the pump and getting more time on the water!

Tilt & Trim On Outboards & Inboards

Not all boats have the same types of engines, and not all engines have the ability to tilt or trim on them.

We wrote a great article that explains all about the many differences between the types. So if you want to know more about the different types, you can read this article about the differences between inboards and outboards.

On outboards, the tilt and the trim feature is used on almost all of the engines. Some smaller engines will not have power tilt and trim, but will have the ability to tilt them up out of the water. The trim feature might not be available though.

Then on inboard engines, this mainly deals with sterndrives and I/O’s. Where the outdrive of the engine can trim up a little bit, but there isn’t really a tilting feature for them.

This is understandable because as we talked about. The trim is only for the first 20 degrees and then tilting is everything above that. Where on a sterndrive, there are only about 20 degrees of overall motion. So there isn’t any tilting that would be needed.

The Efficiency In Trimming Up While Driving The Boat

There is a lot of efficiencies to running trim in your engine while you are underway. Probably the most important and the one that we all care about. Is fuel efficiency and how better our fuel economy is when we add a little trim in the engine.

There are some parameters that we want to run in though. You won’t get anything from trimming the engine up if the boat is not on a plane. This basically means whenever the boat is running at cruising speed and is “on top” of the water.

You can tell if the boat is on a plane by looking back at the wake coming from under the boat. Usually, after around 3,000 RPM’s, most boats will be on a plane. You can run your boat at normal cruising speed and then slowly bring the throttle back.

Whenever you lose sight of the smooth water coming off the bottom of the boat behind it. And you feel the back of the boat sink down into the water and the bow goes up. That is your hulls planing speed. Or the RPM’s that it falls off the plane.

So, while on a plane, if you trim the engine up, and all boats will have different trim angles depending on the power and the hull. You will feel the boat come up more out of the water.

That is because the propeller does not have an upward angle to it. When the engine is trimmed all the way down. The propeller will be at an angle that will be pointing slightly upward, towards the surface of the water.

This angle will push the bow of the boat down into the water and create more drag on the boat. Making the engine consume more fuel,

costing you more money!

So if we trim the engine up, it will change the angle of the propeller to be facing more downward, into the water. This will push the bow of the boat up out of the water, removing drag and getting more of the boat out of the water.

With less drag, the engine will not need to consume as much fuel and you will also gain speed!

There is a thing as too much trim though. If you trim the engine up too much, it will begin to throw a huge rooster tail and that will actually take away your speed, for most recreational applications.

That is because you will be running the prop out of the water and piercing the surface of the water, sucking in air. That is called ventilation and you are aerating the prop, making for prop slip. This is where the propeller loses it’s grip on the water, because it is cutting through the air, and not the water.

The Effects Of Not Tilting Up

Since we’ve talked a lot about the trim, and not so much about the tilt. It’s important to know why tilt is so important.

Not only is it incredibly important to tilt the engine up when trailering it. It is also necessary to tilt the engine up out of the water when the boat is left in the water for long periods of time.

I’m sure for most of you, this is a pretty obvious topic. But not everyone has as much experience with boats, so it’s important to touch on it.

If an engine is left down in the water for too long. It will develop a lot of growth on the engine, which is damaging to the engine and will also slow down the performance of the boat.

So, if you are going to leave the boat in the water for an extended period of time, you want to make sure that it is tilted up out of the water to prevent this growth.

We have two articles that have some really detailed information that will be a great read for you on this subject.

Should I leave my outboard engine up or down? Plus Boat Storage Tips.

Moving a boat from freshwater to saltwater? 10 Tips to Know!

Trim Limiters

Over the years, the marine industry has made incredible advancements and there are all kinds of new features coming on newer engines.

Lots of engines built in the last 20 years or so have the ability to have trim limiters on them. What these do, are they limit the ability to trim the engine.

This is usually used on certain boats that have jack plates, engines mounted high, or engines that will hit the transom when they are tilted up out of the water.

What these do are just to stop the engine from tilting up past a set point that is configured by a technician or the boat builder.

This is just important to know about and can be useful if you have a problem with hitting the transom or your poling platform when you are poling the flats or trailering the boat!

Servicing The Tilt & Trim Unit & Tilt Trim Fluid

The trim and tilt unit is also something that gets forgotten about. Whenever you perform your normal services. It is something that should be looked at. It’s a great idea to have your boat on a service schedule or have yourself on a service routine to take care of your engine.

You can add a lot of life to your engine if it is properly maintained! We’ve also got some more extremely helpful information in this article here on How You Can Add More Hours To Your Boat’s Engine!

Checking the fluid level and then checking the seals. We want to make sure that they are not leaking, rusting, or beginning to leak. Will help you to prevent them from failing and then allowing water to get inside of the trim and tilt unit. Causing failure down the road!

Trim and tilt units can be filled up with the same fluid on each unit. All manufacturers make a certain fluid that you can purchase. Or you can fill the unit with automatic transmission fluid Dexron 3, or what is known as ATF.

ATF is a universal fluid that can be used on your power trim and tilt system.

We have a great video on servicing a trim and tilt system seals here on our Youtube Channel:

Tilt & Trim Vs. Trim Tabs

Sometimes tilt and trim can get confused with trim tabs. Trim tabs are completely different from the engine’s trim and tilt system though. Trim tabs are used to straighten out the boat or compensate for heavy loads on one side or the other of the boat.

We know that the trim is used to get more of the boat out of the water when running, and for storing the engine.

What trim tabs do is create a drag on one side of the boat, or they push the bow down into the water. This is extremely useful in certain offshore currents or river currents as well. You can put one trim tab down and that will make the boat list in one direction.

We want to put the list into the current, to compensate for the current pushing the boat in a certain direction. You can also do this a little bit with the engine trim and keeping one engine down. But this requires twin engines to do.

It can be done by leaving one engine down and then trimming the other engine up!

Check Us Out!

Now you know all about your engine’s trim and tilt system and what it is used for! For even more information and helpful videos. Check us out on Youtube! We creat all kinds of how-to and DIY videos to help you learn more and more about your boat and how it works!

Aaron Hilligoss

Aaron has been working in the Marine Industry for over a decade and holds certifications for Yamaha and Mercury Marine. It is not uncommon for him to own and be working on at least three different boats at any given point in time!

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