Mercury Marine Gaskets, Seals, O-Rings, and Grommets

A blown Mercury Marine gasket, seal, o-ring, or grommet can ruin a day on the water. Shop PartsVu’s comprehensive selection of certified Mercury marine outboard gaskets, seals, O-rings, and grommets.

Mercury Outboard Engine Gaskets, Seals, O-Rings, and Grommets Resources and Information

PartsVu is happy to offer a wide selection of certified Mercury outboard engine gaksets, seals, o-rings, and grommets to replace your damaged or worn out marine engine parts. Need help choosing the right Mercury outboard parts? Take a look at our guide on how to select the right parts for your Mercury outboard over on our blog.

We also regularly publish helpful resources to help you maintain your Mercury outboard motor, such as:

Mercury Marine Gaskets, Seals, O-Rings, and Grommets FAQs

How do I select the right parts for my Mercury outboard motor?

PartsVu’s Mercury Outboard Maintenance Parts Library is the perfect reference when you need to replace common parts. That’s because these parts charts make it simple to find the right parts for your particular engine to perform regularly-scheduled maintenance.

For Mercury outboard motors, perform maintenance after 100 hours of service or one year of operation (whichever comes first). More extensive service is recommended after 300 hours of service or three years.

After this period, maintenance is often more regular as the engine ages and parts wear out. For example, 1,000 hours generally requires an in-depth assessment by a qualified mechanic. Also, if you’re usually running your Mercury outboard in a more demanding manner, the manufacturer recommends more frequent servicing.

When selecting the correct Mercury Outboard Parts, there are some essential things every boater must keep in mind before purchasing and installing parts:

Choosing Mercury OEM parts (original equipment manufacturer) over after-market parts often yields better long-term results for your engine as these components and products are specifically designed to meet the precise tolerances of Mercury engines.

Check (and recheck) to ensure that you have the exact part number that matches your Mercury outboard engine. It’s important to do this because Mercury has many engine models that look very similar but contain slight differences in performance. Therefore, unmatched parts may not fit uniformly, leading to malfunctions, underperformance, and severe engine damage.

Proper maintenance is essential when it comes to extending the life of your Mercury outboard motor and should always be mandatory to retain the value of your outboard motor. While Mercury outboards are built to last, hazards like salt water, humidity, excessive heat, electrolysis, and demanding usage eventually take their toll on your motor.

Proper storage for your Mercury outboard is required to preserve your motor for the long term. Failure to properly winterize your Mercury outboard can cause components to degrade while the engine sits and is exposed to the elements. Therefore, properly store your outboard when it is not in use.

PartsVu offers more than 54,000 genuine Mercury OEM parts and products and other boating essentials at affordable prices. With same business day shipping on in-stock items, PartsVu is always by your side to find the right parts every time. Enjoy optimal performance and lifespan from your Mercury outboard motor today!

How often should I grease my Mercury outboard grease points?

You must grease all points at regular service intervals—minimally, annually. Saltwater boaters need to lubricate much more frequently as saltwater breaks down grease, and saltwater on non lubricated surfaces causes a great deal of damage.

Refer to your owner’s manual to locate all the grease fittings on your specific engine. Most will be easy to find, but a couple are likely tucked away and are not quite as visible. While you must familiarize yourself with the grease fittings on your specific engine, common grease fitting points include:

Steering friction adjustment shaft (tiller handle models)
Swivel bracket
Tilt tube
Steering cable grease fitting

To add grease, first wipe off the grease fitting before attaching the grease gun nozzle to avoid pumping dirt and debris into the grease point. Also, you may have to remove rust and other debris clogging/blocking grease fittings.

Pump grease into the fitting until grease begins oozing out of the exit points of the area being greased. The old grease will be pushed out as it is being dislocated by the new grease. Wipe off the old grease with your rag.

When a given grease point is full, leave a bit of grease on top of the grease fitting to keep rust and other debris from accumulating. Wipe off any excess grease with your rag, then move to the next grease fitting.

While not needed for all scenarios, it is worth noting that Mercury’s High Performance Extreme Grease is formulated for high temperature and high load applications and 100% compatible with lithium-based greases.

Will doing maintenance void my Mercury outboard engine warranty?

Any warranty work done on your engine needs to be done by an authorized Mercury dealer. Your dealer will perform the work on your engine and file the claim with Mercury for you.

Your Mecury’s warranty does not apply to damage or failures caused by use of an accessory or part not manufactured or sold by Mercury. See the appropriate Mercury or MerCruiser warranty policy for your product or in your Operation, Maintenance & Warranty manual. In other words, if you modify your engine with non-Mercury parts and those parts cause damage, you will likely have a problem.

Fuels containing up to 10 percent ethanol are considered acceptable for use in Mercury engines. Fuels containing higher levels of ethanol are not considered acceptable for use, and can void the warranty.

Using the serial number of your engine, your local authorized Mercury dealer can quickly check your warranty coverage. They can verify that your engine is registered with Mercury, whether it is covered by Mercury’s standard factory warranty, if there is any additional promotional coverage, or if it is covered by a Mercury Product Protection plan.

How do I protect my Mercury outboard motor?

Cover it with Corrosion Guard. This rust inhibitor forms a water-resistant barrier on both painted and unpainted surfaces. We recommend using it at every service interval with a liberal application to all metal engine surfaces. You can also use it on outdrives, lower units, and power trim motors.

The marine environment is one of the harshest on the planet. This is why protecting your boat from corrosion is extremely important. For premium defense against rust, we highly recommend this product.

In order to maximize your engine’s performance, use this complete fuel treatment at every fill-up with any grade of gasoline. Quickare is an excellent defense against the problems associated with ethanol-blended fuels, including its corrosive effects on metals as well as the gum and varnish that result from fuel oxidation. See PartsVu’s Knowledge Center for our article on the problems of ethanol gasoline.

This product can also be used to clean up existing deposits in untreated fuel lines, tanks, carburetors, injectors, intake valves, and spark plugs. It will keep your fuel fresh for up to three months and can be used in all 2 and 4 cycle carbureted and fuel-injected gasoline engines. Use one ounce to treat every 10 gallons of fuel.

How do I troubleshoot my Mercury outboard engine?

If your Mercury outboard cranks, but won’t start, there may be an issue that needs correcting.

Most likely, the cause is a low and dying battery. Remove the battery from its housing by first disconnecting the black (negative) cable, and then the red (positive). You can then check the voltage using a voltmeter– it should be at about 12.6 volts. Inspect the battery for damage and clean off any corrosion or other buildup with a wire bristle brush.

Some types of residue can be removed with a mixture of water and baking soda at a ratio of 1 cup:1 tablespoon, respectively. Apply and scrub the mixture over the affected parts. If you choose to do this, be sure to very thoroughly dry the battery before reattaching the cables. Finally, if the voltmeter resulted in a low reading, charge the battery.

In cases where your battery won’t hold a charge, it will of course need to be replaced. In the meantime, you may be able to start the engine manually.

Where can I learn more about Mercury outboard parts?

PartsVu understands that boaters want to learn how to perform their own Mercury outboard maintenance. From maintaining your Mercury outboard, Mercury sterndrive, and MerCruiser engines, there’s always something new to learn and save money.

That’s why PartsVu offers our comprehensive blog, The PartsVu Xchange. Read up on the latest developments in boating, as well as search for everything you need to know about your Mercury motor maintenance.

To get you off to a good start, these are some of the most important articles on Mercury Marine Gaskets, Seals, O-Rings, and Grommets, questions like “How to Troubleshoot my Mercury Outboard Engine”, and much more:

How to replace lower unit seals on Mercury outboard?

Over time, the seals on your Mercury outboard lower unit may become worn or damaged, causing oil leaks or allowing water to enter the unit. If you notice any signs of a leaking lower unit, it is important to replace the seals as soon as possible to prevent further damage. Here are the steps to replace the lower unit seals on your Mercury outboard:

Remove the lower unit: Refer to your owner's manual for instructions on how to remove the lower unit from your specific Mercury outboard model.
Remove the old seals: Using a seal puller or a small screwdriver, carefully remove the old seals from the lower unit. Be sure to clean any residue or debris from the seal grooves.
Install the new seals: Apply a small amount of marine grease to the new seals, then carefully install them into the seal grooves.
Reinstall the lower unit: Refer to your owner's manual for instructions on how to reinstall the lower unit, making sure to properly align the driveshaft and water pump.
Fill with gear lube: Once the lower unit is securely installed, fill it with the recommended gear lube for your Mercury outboard.
Test for leaks: After filling the lower unit with gear lube, run the engine in a test tank or in the water and check for any signs of leaks. If you notice any leaks, address them promptly to prevent further damage.

How to replace prop shaft seal Mercury outboard?

The prop shaft seal on your Mercury outboard is responsible for preventing water from entering the lower unit through the propeller shaft. If you notice any signs of a leaking prop shaft seal, it is important to replace it as soon as possible to prevent further damage. Here are the steps to replace the prop shaft seal on your Mercury outboard:

Remove the propeller: Use a wrench or socket set to remove the propeller from the propeller shaft.
Remove the old seal: Using a seal puller or a small screwdriver, carefully remove the old seal from the propeller shaft. Be sure to clean any residue or debris from the seal groove.
Install the new seal: Apply a small amount of marine grease to the new seal, then carefully install it into the seal groove.
Reinstall the propeller: Use a wrench or socket set to reinstall the propeller onto the propeller shaft.
Test for leaks: After reinstalling the propeller, run the engine in a test tank or in the water and check for any signs of leaks. If you notice any leaks, address them promptly to prevent further damage.

It is always recommended to consult your owner's manual or seek the advice of a certified Mercury Marine technician for guidance on any maintenance or repairs on your Mercury outboard.

How long does a Mercury outboard head gasket replacement take?

The time it takes to replace a head gasket on a Mercury outboard engine can vary depending on several factors, including the size of the engine, the level of damage to the head gasket, and the experience of the mechanic performing the replacement. In general, a head gasket replacement on a Mercury outboard engine can take anywhere from several hours to a full day or more.

To replace a head gasket on a Mercury outboard engine, the following steps are typically involved:

Remove the cylinder head: The first step is to remove the cylinder head from the engine block, which involves removing the valve cover, rocker arms, pushrods, and any other components that may be in the way.
Clean the surfaces: Once the cylinder head is removed, the mating surfaces of the cylinder head and engine block must be thoroughly cleaned to ensure a proper seal with the new head gasket.
Replace the gasket: With the surfaces cleaned and prepped, a new head gasket can be installed onto the engine block and cylinder head.
Reassemble the engine: After the new head gasket is in place, the engine can be reassembled in the reverse order of how it was disassembled, with careful attention paid to proper torque specifications for all bolts and fasteners.
Test for leaks: Once the engine is fully reassembled, it should be started and run for a period of time to check for any leaks or other issues that may need to be addressed.

What's typically included in a Mercury outboard carburetor gasket kit?

A Mercury outboard carburetor gasket kit typically includes a variety of gaskets and O-rings that are needed to rebuild or repair the carburetor on a Mercury outboard engine. The exact contents of the kit can vary depending on the specific model and year of the engine, but here are some of the components that may be included:

Carburetor base gasket: This gasket sits between the carburetor and the intake manifold on the engine block.
Carburetor bowl gasket: This gasket sits between the carburetor bowl and the carburetor body.
Needle and seat gasket: This gasket seals the needle and seat assembly, which controls the flow of fuel into the carburetor bowl.
Fuel pump gasket: This gasket seals the fuel pump to the carburetor body.
Throttle body gasket: This gasket sits between the throttle body and the carburetor body.
O-rings: The kit may also include various O-rings that are used to seal different parts of the carburetor assembly.

It's important to note that the exact contents of a carburetor gasket kit can vary depending on the engine model and year, and some kits may include additional components or may not include all of the components listed above.

How do I perform a Mercury outboard water jacket gasket replacement?

Replacing the water jacket gasket on a Mercury outboard can be a complex and time-consuming task, and it's generally recommended that this type of repair be performed by a certified Mercury Marine technician. However, if you have the necessary mechanical skills and experience, you may be able to perform the repair yourself. Here are the basic steps involved:

Remove the cowling: The first step is to remove the engine cowling to gain access to the cylinder head.
Drain the cooling system: Before removing the cylinder head, it's important to drain the cooling system to prevent coolant from spilling out onto the engine or into the bilge. This can typically be done by loosening the drain plug on the lower part of the engine block.
Remove the cylinder head: With the cooling system drained, you can remove the cylinder head from the engine block. This typically involves removing various bolts and fasteners that hold the head in place.
Clean the surfaces: Once the cylinder head is removed, you'll need to clean the mating surfaces of the head and engine block to remove any debris or old gasket material.
Install the new gasket: With the surfaces cleaned, you can install the new water jacket gasket onto the engine block, taking care to align it properly with any coolant passages or other openings.
Reassemble the engine: After the new gasket is in place, you can reassemble the engine in the reverse order of how it was disassembled, paying close attention to torque specifications and other installation requirements.
Refill the cooling system: Once the engine is fully reassembled, you can refill the cooling system with the appropriate coolant and check for any leaks or other issues.

Again, this is a very basic overview of the water jacket gasket replacement process, and the exact steps involved can vary depending on the engine model and year. It's always recommended to consult with a certified Mercury Marine technician or reference the engine's service manual for guidance on any maintenance or repairs.

Is a Mercury outboard engine oil drain plug gasket and a Mercury outboard lower unit drain plug gasket the same thing?

No, a Mercury outboard engine oil drain plug gasket and a Mercury outboard lower unit drain plug gasket are not the same thing. The engine oil drain plug is located on the engine block and is used to drain the oil from the engine crankcase. The lower unit drain plug is located on the lower unit of the outboard motor and is used to drain the gear oil from the lower unit. The gaskets used for these drain plugs may be different in size and material. It is important to use the correct gasket for each drain plug to ensure a proper seal and prevent leaks.

What are some common seal replacements for Mercury outboard motors?

Some common seal replacements for Mercury outboard motors include the cowling seal, crankshaft seal, drive shaft seal, lower unit seal kit, lower unit seal replacement, lower unit seals, shift shaft seal replacement, tilt and trim seals, and water tube seal. It is important to regularly check and replace these seals to prevent water from entering the engine and causing damage.

Shop PartsVu for Mercury Outboard Cowling Seal | Mercury Outboard Lower Unit Seal Kit | Mercury Outboard Lower Unit Seals | Mercury Outboard Tilt And Trim Seals | Mercury Outboard Water Tube Seal

How long does a Mercury outboard fuel connector o ring and a Mercury outboard fuel tank connector o-ring last?

Mercury outboard o rings degrade over time. Generally speaking, the lifespan of a Mercury outboard fuel connector o ring and a Mercury outboard fuel tank connector o-ring can vary depending on several factors such as usage frequency, exposure to weather and elements, and overall maintenance of the engine and fuel system. Generally, these o-rings should be inspected regularly and replaced as needed, particularly if they show signs of wear, cracking, or damage. A good rule of thumb is to replace them every few years or sooner if necessary.

What comes with Mercury outboard seal kits?

Mercury outboard seal kits typically include various seals, o-rings, and gaskets that are necessary for maintaining a watertight seal on different parts of the outboard motor. The exact contents of a seal kit can vary depending on the specific model and year of the outboard, but some common components include prop shaft seals, gear case seals, water pump seals, and exhaust plate gaskets. These seal kits can help prevent water from entering the motor and causing damage, and they are often recommended for routine maintenance to ensure the longevity and reliability of the outboard.

Does PartsVu sell Mercury outboard parts 25 hp 2009 fuel injector o rings?

Yes, we offer fuel injector O-rings for 25 HP 2009 Mercury outboard engines on PartsVu.com. Browse our selection of genuine Mercury OEM parts to find the specific O-ring kit that you need for your engine.

How do I perform a Mercury outboard powerhead gasket replacement?

Replacing a powerhead gasket on a Mercury outboard can be a complex process and may require special tools and expertise. It is recommended to refer to the manufacturer's service manual for detailed instructions specific to your outboard model. However, in general, the steps for a powerhead gasket replacement may include:

Remove the lower unit and disconnect all electrical and fuel lines from the powerhead.
Remove the intake and exhaust manifolds, carburetors, and flywheel.
Disconnect and remove the powerhead from the midsection.
Remove the cylinder head bolts and lift the cylinder head off the block.
Scrape off any rem