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How To Use Sea Foam In An Outboard Motor (2, 4-Stroke)?

How To Use Sea Foam In An Outboard Motor (2, 4-Stroke)?

Whether you are an experienced seafarer or a newbie marine enthusiast, your boat’s engine will get dirty. In this article, we will take a look at Sea Foam products as a way of cleaning an outboard motor.

Using Sea Foam Motor Treatment to clean your outboard motor is a great way to ensure that your motor stays healthy and will serve you for a long time. 

Keep reading if you want to know all about using Sea Foam to clean your engine!

Using Sea Foam is simple–you just need to pour it into your gas tank before adding fuel. Then leave the engine running for 20 minutes.

Why Use Sea Foam To Clean Your Engine?

two men bringing the outboard boat motor

The internal parts of your engine will get clogged up over time. Varnish and tar will build up in the crankcase, where your oil is stored. They will also build up all over the rings, lifters, pistons, and galleys that transfer oil to all other components.

This means that oil won’t be able to flow where it needs to. This will affect your engine by reducing its ability to lubricate and cool itself, which will reduce its life, performance, and efficiency.

Buildup can also occur inside the fuel system of your engine. It will clog the carburetor jets and the injectors while gumming up the intake valves. If those valves can’t move freely, your engine’s ability to breathe will be greatly handicapped.

Also, deposits of carbon can develop on the valves and pistons. This can create hot spots which are capable of causing detonation.

It doesn’t stop there. Carbon can build up in areas along the engine intake tract, which will greatly hamper the airflow.

What does all of this mean? It means that you need to clean these places regularly. Since they are hard to reach, this can be difficult.

However, by using Sea Foam products, you can keep things clean more easily. Let’s see how these products work.

What Are Sea Foam Products?

Sea Foam motor treatment and Sea Foam deep creep

Sea Foam has been around for more than 70 years. Most marine aficionados regard it as one of the simplest and most useful treatments for the engine.

Sea Foam has a range of products, but the company is best known for the Sea Foam Motor Treatment. This product is specifically made to slowly and safely clean the hard-to-reach parts in your engine. 

This product re-liquifies the gum, varnish, sludge, and carbon deposits so they can be easily removed from the system of your engine.

By using Sea Foam, you will help lubricate the moving parts of your engine. This is especially true when talking about the fuel system.

Various ethanol additives will dry out the seals in the fuel system over time. They leave a varnish that makes it more difficult for the oil to lubricate parts of the engine. 

Sea Foam products will remove this varnish and will help bring your engine back into excellent working order.

Sea Foam products also absorb water, which means that they won’t cause any issues inside the combustion chamber.

To conclude this segment, Sea Foam is a fuel additive that is used to clean and lubricate the engine of a boat. The following steps outline the basic process for using Sea Foam in an outboard engine:

How To Use Sea Foam In 2-Stroke Outboard Engines

Parsun two-stroke outboard motors

First, let’s take a look at how to use Sea Foam products in a 2-stroke outboard engine. Of course, it is always useful to read the instructions found on the packaging as well.

  • Obtain a can of Sea Foam and make sure your fuel tank is at least 1/4 full.
  • Shake the Sea Foam well and add the entire can to your fuel tank.
  • Fill the rest of your fuel tank with fresh gasoline.
  • Run the engine normally for 15-20 minutes.
  • If the engine runs smoothly, continue using it normally. If the engine runs poorly, drain the fuel tank and carburetor, then refill with fresh gasoline.

How To Use Sea Foam In 4-Stroke Outboard Engines

Suzuki four-stroke outboard motors attached on a boat

Now, let’s see how to use these products in a 4-stroke outboard motor.

  • Obtain a can of Sea Foam and make sure your oil and fuel are at normal levels.
  • Shake the Sea Foam well and add the entire can to your fuel tank.
  • Fill the rest of your fuel tank with fresh gasoline.
  • Run the engine normally for 15-20 minutes.
  • Change the oil after running the engine with Seafoam, following the manufacturer’s recommended oil change procedure.

Note: Always refer to the manufacturer’s recommendations for specific instructions for your engine, and always follow all safety precautions when working with fuel.

The Different Sea Foam Products

There are slight variations in how to use different Sea Foam products. Let’s take a look at some of these variations.

1. Sea Foam Motor Treatment

Sea Foam SF-16-2PK Motor Treatment Multi-Use, 16 Ounce, Pack of 2, 16. Fluid_Ounces
  • Dissolves and clean fuel deposits and sticky residues from gas and diesel fuel injectors, carburetors, and combustion chambers
  • Package dimensions :5.0" L x5.0" W x8.25" H

Last update on 2024-06-14 at 03:47 / Affiliate links / Images from Amazon Product Advertising API

Sea Foam Motor Treatment is an additive used either in the fuel tank or in the oil.

After being poured into the fuel tank, it will clean out deposits and lubricate the entire system. This means that it will lubricate the injectors, lines, and intake valves. It will also lubricate the upper parts of the engine’s cylinders.

If you use it in the oil, it will help liquefy the gunk and sludge buildup and help your engine run better than before. You can expect this product to clean the entire system, including oil control rings, actuators, and VVT solenoids.

You shouldn’t use this product in the oil more than once per oil change. The best time to use it is before you perform an oil change so that it removes all the dirt from the system.

It can also be used to stabilize the fuel in storage, which will lower vaporization.

  • Using Sea Foam Motor Treatment In The Gas Tank

You can use Sea Foam Motor Treatment in both diesel and gasoline engines.

The spout of a big funnel should fit into the filler neck. Pour Sea Foam into the tank through the funnel.

Pour only a small amount at a time to prevent spills.

Use one ounce of Sea Foam to one gallon of fuel under normal conditions.

To effectively clean your fuel system, you need two or more ounces of cleaner per gallon of fuel. But there is no restriction. The cleaning process will be more efficient the more product you use. No component of a gas or diesel engine will be harmed by Sea Foam Motor Treatment.

You should pour the Sea Foam product when your tank is low. By doing this, it will be forced through the system more efficiently and the cleaner will have a larger impact.

  • Using Sea Foam Motor Treatment In The Oil

This is also a pretty simple process. You just need to pour the Sea Foam Motor Treatment into the oil container.

Remove the oil filler cap, and use a funnel so that you make sure not to spill any Sea Foam. For every quart of oil, you should pour an ounce of Sea Foam.

Check the owner’s manual to see how much oil your boat’s engine can take and use the correct amount of Sea Foam once you know.

2. Sea Foam Spray

Last update on 2024-06-14 at 04:47 / Affiliate links / Images from Amazon Product Advertising API

Now, let’s take a look at a different product, the Sea Foam spray.

First of all, using Sea Foam spray is best left to professional mechanics. It is a fairly complex process that shouldn’t be attempted by a beginner. If you make a mistake, you could damage the MAF (Mass Air Flow) sensor on your motor.

This spray is specially designed to be used in the upper parts of the engine that can’t be reached with regular fuel cleaners. This includes parts such as the valves, the intake manifold, and the bushings.

Some of these aren’t cleaned by fuel additives because the fuel never actually goes past them.

Sea Foam spray is designed for all 2-stroke and 4-stroke gas engines. You do not want to use this one for diesel engines!

As we already mentioned, you need to be sure not to spray this product onto the MAF sensor. If you plan to use this spray, read and follow the instructions carefully!

Again, we advise you to seek the help of a professional mechanic if you plan to use this product.

Otherwise, you could do some damage to your engine.

3. Sea Foam Fuel Injector Cleaner

Sea Foam IC5 Fuel Injector Cleaner, 5.25 oz
  • Treats Up To 25 Gallons ps, lost acceleration and rough idling for improved performance
  • Jet fuel serves as the carrier for the active ingredien Helps Recover Lost Mpg And Reduce Exhaust Emissionst nts, creating a high-quality additive for easy auto care

Last update on 2024-06-14 at 04:47 / Affiliate links / Images from Amazon Product Advertising API

This is another product aimed solely at gasoline engines. Those with a diesel engine should not use this one.

This product is designed to clean your fuel injectors, and the method is quite simple. 

  • First, open the bottle and push its neck directly into your fuel tank. The bottle has a long neck, so you can pour the product directly without needing a funnel.
  • Pour the entire content of the bottle. The best time to do this is when your tank is low, as it will improve the effectiveness of the cleaning process.

That’s it! It is incredibly simple, and it is recommended to add this injector cleaner whenever you fill up the tank. This will provide you with the best performance. However, it is not a very cost-effective option.

4. Sea Foam Ultimate Oil Stabilizer

Last update on 2024-06-14 at 04:47 / Affiliate links / Images from Amazon Product Advertising API

This product is specially designed to protect your engine from sludge buildup. You will need to pour it during an oil change, meaning it might not be as simple to use as some other products.

You can always tell a mechanic to do this for you. But basically, you use a quart of this product for every quart of engine oil during an oil change

This product is also used only for gasoline engines.

Are There Any Negatives To Using Sea Foam?

Not everything is perfect, and neither are Sea Foam products. There are people that claim that there could be some negative aspects of using them.

Some of the most common complaints refer to the older formula, so you should keep in mind that the formula used by the manufacturer has changed over time.

However, some complaints can still be valid, and we feel that we need to mention them.

The most important downside is that using Sea Foam can thin out your oil or reduce its viscosity.

Oil is an incredibly important component of any vehicle, as it lubricates multiple parts. Its primary function, of course, is that it lubricates the engine.

Using Sea Foam products may thin out the oil and make it run out much faster, which can be a serious issue. You don’t want your oil to ever run out since it is a crucial component to keeping your engine lubricated and fully functional.

outboard motor of an inflatable boat discharges waste oil into the water

Another possible downside is that it can end up creating more sludge! Yes, even though the product is designed to get rid of sludge, it can actually do the opposite. If this happens, your engine will be at risk of malfunctioning.

More sludge means that your engine will overheat quickly, which can create serious issues. However, this problem is not that common and does not happen regularly.

Finally, Sea Foam may negatively affect your gas efficiency. This can happen if you use a larger amount of Sea Foam than recommended, so it is important to be careful.

That’s about all of the negatives that may happen when using these products. Keep in mind, they only happen rarely, so you should be perfectly fine if you follow the instructions and use Sea Foam properly.


Using Sea Foam is a great way to keep your outboard motor clean and healthy. You just need to follow a few simple steps.

Add it to your gas tank before adding fuel, then run the engine normally for about 20 minutes. That should keep it clean and healthy.

However, there are more complex instructions for some specialized Sea Foam products. Do not expect these products to fix an engine that is failing. However, if you use them regularly, they can keep your outboard motor clean and highly functional for a long time.

If you have any questions, leave them in the comments.