Mercury Marine Oils, Lubricants, and Additives

Mercury Marine Engine Lubricants, Oils, and Additives Resources and Information

PartsVu.com is happy to offer a wide selection of certified Mercury outboard and MerCruiser lubricants, oils, and additives to match the exact specifications of your Mercury outboard or inboard engine. If you need assistance servicing your Mercury engine, follow along with these helpful guides over on our blog: Mercury fuel system 100-hour service, Guide to Mercury Marine Precision Oils and Lubricants.

Browse the rest of our complete selection of Mercury outboard parts, MerCruiser parts, or shop our list of Mercury lubes, oils, and additives categories, including: 

• Mercury Precision Lubricants Engine Oil
• Mercury Marine Gear Lube & Power Trim Fluid
• Mercury Corrosion Inhibitors & Grease
• Mercury Marine Fuel Additives & Fogging Oils
• Quicksilver Marine Engine Oil
• Quicksilver Marine Fuel Additives & Fogging Oil

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

• Mercury Outboard Service Schedule
• Mercury Outboard Specs & Capacities Chart
• Mercury Outboard 100-hour Service Guides
• How to Select the Right MerCruiser Parts

• MerCruiser Engine Oil Capacities Chart

Mercury Outboard & MerCruiser Lubricants and Oils FAQs

How do I change my Mercury 4-stroke outboard engine oil?

As the old oil is draining, you can work on removing the engine oil filter. Depending on your specific Mercury model, your filter may have a drain lip that helps to keep the mess to a minimum when you unscrew the old filter. However, most older engines do not have this feature. We suggest being prepared with plenty of absorbent rags or placing a small cup that is cut to size below the filter before removal. Using a PartsVu Maintenance Essentials filter wrench is the best way to loosen the filter. Remember when you reinstall the filter, over-tightening will only make your life more difficult when you are ready for the next service. Some technicians puncture the old filter allowing trapped oil to drain back into the block before removal, but this will ruin your ability to take the filter apart for further inspection.

Several laboratories provide performance testing of used oils, allowing you to learn more about the health of your engine. Blackstone Labs is one such provider, and they have a convenient mail-in kit that includes everything you need to submit an oil sample. They can also test gear oils, hydraulic fluids, and oils from your other vehicles or toys. Oil test results can tip you off to an accelerated wear condition inside of your engine long before any other symptoms show up. If you still want to know more about your engine, purchase an oil filter cutter and open the spent filter to look for evidence of contamination and metal dust or shavings.

Once you have inspected your spent oil and filter, set them aside for proper disposal. If you removed the drain screw to empty your oil, carefully reinstall the drain plug. The new oil filter should be removed from its package and the o-ring lubricated with a thin coat of fresh engine oil. Spin on the new oil filter and gently tighten to seat the o-ring without over-torquing.

Mercury Marine offers a wide assortment of engine oil – both in blend and viscosity. If you are uncertain as to which oil is best for your application, consult your owners’ manual. Loosen the yellow oil fill plug on the top of the engine and pour in fresh oil. We recommend adding slightly less than the stated capacity. With the engine trimmed down, check the oil level on the dipstick after allowing a few minutes for the oil to drain into the oil pan properly. Filling the oil to the lower level on the dipstick will help you to measure if the oil level changes over time with the engine in operation.

Why should I use Mercury fuel additives?

Quickare treats and stabilizes fuel at every fill-up which is necessary because just about all gasoline today contains up to 10% ethanol. Left untreated, ethanol-blended fuel can break down leading to gum and varnish build-up which causes internal engine corrosion. Fuel additives such as a bottle of Quickare keep fuel fresh between fill-ups for up to three months.

The second step within Mercury’s fuel care system cleans your engine and fuel system. All combustion motors develop carbon deposits and the best way to clean those deposits is to add Mercury Quickleen to your fuel tank. Simply add a bottle of Quickleen to your outboard fuel tank once per year to remove carbon deposits, prevent engine knocking, piston seize up, and extend spark plug life. Aggressive fuel system cleaner within Quickleen works to quickly and thoroughly remove carbon deposits from carburetors and fuel injectors, intake valves, spark plugs, piston crowns, and cylinder heads.

Likely, there are periods when your boat is stored or is used infrequently, which can lead to issues with your engine running. If your boat will be sitting for an extended period of time, you need to add a fuel stabilizer like Mercury Marine Quikstor to prevent both regular and ethanol-blended fuels from breaking down, oxidizing, and causing fuel system corrosion, and eventually affecting the engine’s performance. Before storage add a bottle of Quickstor to your fuel tank, then run the engine so that the treated fuel circulates throughout the engine and fuel lines. This extended fuel stabilizer prevents gum and varnish from forming in the engine, fuel lines, and tank and stabilizes fuel for up to one year, thereby successfully averting any fuel-related problems. One ounce of Quickstor treats five gallons of fuel, so a 12-ounce bottle treats 60 gallons.

How do I service my Mercury 2-stroke outboard motor grease points?

Note that fittings can be contaminated by salt – especially the ones near the steering tube – so replace them if they are too corroded to accept grease. Watch as you pump fresh grease into the fitting and see if old, dirty grease or water or both push out from the corresponding space. Ideally, these cavities are filled with clean grease all the time. A light coating of grease on the tip of the trim rams will reduce friction there as well. If your engine is equipped with stainless balls on the tips of the trim rams, work the balls to get the grease inside their cup.

If your prop was not removed for the gear lube change, remove the cotter pin or lock washer from the propeller and loosen the prop nut. Exercise extreme caution as prop blades can be very sharp. With the nut loosened, remove the propeller and associated prop hardware to inspect the propeller shaft.

Look for fishing line that may be behind the prop and near the prop shaft oil seals. Remove any line and if the seals are intact, apply a fresh coating of Mercury 2-4-C grease to the propeller shaft before reinstalling the prop. Tighten and use a new cotter pin to complete the installation if applicable.

Be aware that your boat’s propeller functions like your vehicle’s tires. Wear on the edges of the propeller can reduce traction, causing speed and fuel efficiency loss. Propeller reconditioning or replacement should be considered if you note wear, rounded edges, thin blades, or cracking. You should also inspect, and replace as needed, the hub inside the propeller. Cracking or wobbling can indicate a worn or damaged hub.

This is also a great time to inspect your external engine anodes. Anodes worn beyond 50 percent should be replaced. Be sure to select the correct sacrificial alloy. The proper sacrificial alloy will depend on whether you boat in salt or freshwater. Spend an extra couple of minutes to check fitment because different propeller selections will not work with all anodes.

On the powerhead itself, corrosion inhibitor can be liberally applied to the metal surfaces, taking some care to avoid the air intake itself. We recommend Boeshield’s T-9 brand, but any high-quality marine corrosion inhibitor will help. If any salt residue exists on the engine, rinse with a light stream of fresh water before applying T-9. This product also works well on battery connections, fuel/water separator bases, and trailer parts.

If you have exposed metal surfaces on your lower unit, trim assembly, steering tiller arm, or trim motor itself, consider purchasing a can of Mercury’s Corrosion Guard to supplement paint on these surfaces.

How to lubricate Mercury outboard throttle cable? / How to lubricate a steering cable for Mercury outboard? / How to lubricate Mercury outboard control cables?

Lubricating the throttle and control cables on your Mercury outboard is an important part of routine maintenance. Here are the steps to follow:

1. Identify the Cables: Locate the throttle and control cables on your outboard. These are typically located near the control box or the engine and are usually covered by a protective sheath.
2. Remove the Sheath: Use a pair of pliers or a wrench to loosen the nut or bolt that secures the sheath in place. Once the sheath is loose, slide it off of the cable.
3. Apply Lubricant: Apply a small amount of lubricant to the exposed cable. You can use a specialized cable lubricant or a light oil such as WD-40.
4. Work the Cable: Move the control lever back and forth to work the lubricant into the cable. This will help to distribute the lubricant evenly and ensure that the cable moves smoothly.
5. Replace the Sheath: Slide the protective sheath back over the cable and tighten the nut or bolt to secure it in place.

Note: Avoid using grease or oil to lubricate control cables as they can attract dirt and debris, which can cause the cable to stick. It is best to use a silicone spray lubricant specifically designed for use on control cables.

How to lubricate Mercury outboard steering? / How to lubricate steering linkage Mercury outboard?

Lubricating the steering and steering linkage on your Mercury outboard is another important part of routine maintenance. Here are the steps to follow:

1. Identify the Steering Components: Locate the steering components on your outboard. These typically include the steering arm, the steering cable, and the steering linkage.
2. Clean the Components: Before lubricating the steering components, clean them thoroughly using soap and water. This will help to remove any dirt, grime, or other debris that may be present.
3. Apply Lubricant: Apply a small amount of lubricant to the steering components. You can use a specialized marine grease or a light oil such as WD-40.
4. Work the Components: Move the steering wheel back and forth to work the lubricant into the steering components. This will help to distribute the lubricant evenly and ensure that the steering operates smoothly.
5. Reapply as Needed: Check the steering components regularly and reapply lubricant as needed to maintain smooth and reliable steering.

What is the best 2-stroke oil for Mercury outboard engines?

Choosing the right 2-stroke oil for your Mercury outboard is important for maintaining reliable performance and protecting your engine from wear and tear. Here are some factors to consider:

1. Manufacturer Recommendations: Check your Mercury outboard owner's manual or consult with a professional mechanic to determine the manufacturer's recommendations for 2-stroke oil.
2. TC-W3 Certification: Look for a 2-stroke oil that is certified to meet the TC-W3 standard. This ensures that the oil provides adequate lubrication and protection for your engine.
3. Synthetic vs Conventional: Consider whether you prefer a synthetic or conventional 2-stroke oil. Synthetic oils generally offer better performance and protection, but can be more expensive.
4. Brand Reputation: Choose a reputable brand of 2-stroke oil, such as Mercury, Yamaha, or Evinrude, to ensure high quality and reliability.

Ultimately, the best 2-stroke oil for your Mercury outboard will depend on your specific engine and usage needs. Consult with a professional mechanic or do research to find the best option for you.

How long does changing gearcase lubricant on Mercury outboards take for DIY mechanics?

The time it takes to change the gearcase lubricant on a Mercury outboard can vary depending on the experience level of the DIY mechanic, as well as the specific model of the outboard. However, in general, the process should take around 30 minutes to an hour for a person with some experience performing basic maintenance tasks on their outboard.

Here are the general steps involved in changing the gearcase lubricant on a Mercury outboard:

1. Remove the gearcase drain plug: Locate the gearcase drain plug and remove it using a socket or wrench.
2. Drain the old lubricant: Allow the old lubricant to drain completely into a suitable container.
3. Inspect the old lubricant: Check the drained lubricant for any metal shavings, which can indicate internal gear damage.
4. Install the new drain plug: Install the new gearcase drain plug and torque it to the proper specifications.
5. Fill the gearcase with new lubricant: Locate the gearcase fill plug and remove it. Fill the gearcase with the recommended type and amount of lubricant until it reaches the proper level.
6. Install the fill plug: Once the gearcase is filled with new lubricant, reinstall the fill plug and torque it to the proper specifications.
7. Check for leaks: Start the outboard and run it for a few minutes while checking for any leaks.

It is important to follow the manufacturer's recommendations for the type and amount of lubricant to use, as well as the torque specifications for the drain and fill plugs. If in doubt, consult the owner's manual or a professional mechanic for guidance.

What are the signs of failing Mercury outboard steering lubrication?

If the lubrication of the steering system in your Mercury outboard is insufficient or failing, you may notice some of the following signs:

1. Stiff or hard steering: If you find that it is difficult to turn the steering wheel, this can indicate a lack of proper lubrication in the system.
2. Clicking or grinding noises: A lack of lubrication in the steering system can cause metal-to-metal contact, resulting in clicking or grinding noises when turning the steering wheel.
3. Vibration or shaking: A failing steering system may cause the boat to vibrate or shake while underway, particularly at higher speeds.
4. Steering wheel not returning to center: If the steering wheel does not return to its center position after making a turn, this could indicate a problem with the steering system, including a lack of proper lubrication.
5. Leaking fluid: If you notice any fluid leaks around the steering components, this can indicate a problem with the seals or other components in the steering system.

If you experience any of these symptoms, it is important to address the issue as soon as possible. Lack of proper lubrication can cause excessive wear and tear on the steering system, leading to more serious and costly issues over time. It is recommended to regularly check and maintain the steering system lubrication according to the manufacturer's recommendations to prevent any problems from occurring.

What comes with a Mercury oil change kit?

The exact contents of a Mercury oil change kit can vary depending on the specific model and year of your outboard engine. However, a typical Mercury oil change kit usually includes the following items:

1. Mercury engine oil: The kit includes the required amount of engine oil recommended for your specific model.
2. Oil filter: A new Mercury oil filter is included in the kit to replace the old one.
3. Drain plug gasket: A new drain plug gasket is included to ensure a proper seal and prevent leaks.
4. Instructions: The kit may include instructions on how to perform an oil change on your particular model of Mercury outboard engine.
5. Optional items: Some oil change kits may also include additional items such as gear lube, fuel filter, and other necessary items for a complete maintenance service.

It is important to check the contents of the kit before purchase to ensure that you have all the necessary items for a successful oil change. It is also recommended to follow the manufacturer's instructions for the specific model of your Mercury outboard engine to ensure proper oil change and maintenance procedures are followed.

Can I use Mercruiser gear lube for my Mercury outboard?

No, you should not use Mercruiser gear lube for your Mercury outboard. While both Mercruiser and Mercury are brands owned by the same parent company, they have different gear lubricants formulated specifically for their respective products. Mercruiser gear lube is designed for inboard/outboard sterndrive applications, while Mercury outboards require their own specific gear lubricant. It is important to always use the recommended gear lubricant for your specific engine to ensure optimal performance and protection.

What's the right ratio for Mercury 2 stroke oil?

The right ratio for Mercury 2-stroke oil depends on the specific model and year of your Mercury outboard engine. Generally, most Mercury 2-stroke outboards require a fuel-to-oil ratio of 50:1, which means 50 parts gasoline to 1 part oil.

However, it's always best to consult your engine owner's manual or check with a certified Mercury dealer to ensure that you are using the correct ratio for your specific engine. Some older models or high-performance engines may require a different oil-to-fuel ratio. Using the wrong oil-to-fuel ratio can lead to poor engine performance or even engine damage, so it's important to get it right.

What does it mean if I discovered metal shavings in my Mercury marine oil?

If you discovered metal shavings in your Mercury marine oil, it is likely a sign of a serious problem within your engine. Metal shavings in the oil can indicate that internal engine components, such as bearings or gears, are wearing down and creating metal debris.

The presence of metal shavings in the oil can cause damage to other engine components and significantly reduce the lifespan of the engine if not addressed promptly. If you see metal shavings in your oil, it is essential to have your engine inspected by a qualified Mercury dealer or mechanic as soon as possible.

Possible causes of metal shavings in the oil include worn or damaged bearings, damaged gears, or other internal engine damage. It is best to have a professional diagnose the root cause of the metal shavings to ensure that the problem is fixed properly and prevent any further damage to your engine.

Where can I learn more about Mercury engine lubricants and Mercury outboard maintenance?

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 outboard maintenance.

To get you off to a good start, these are some of the most important articles on Mercury Precision Family of Lubricants, Oils, Additives, and more:

• How To Protect Your Mercury Outboard
• Guide to Mercury Marine Precision Oils & Lubricants
• Mercury Outboard Grease Points – Here's How
• Mercruiser Oil Change In 8 Easy Steps