Mercury Precision Lubricant and Engine Oil

Mercury Precision Lubricant and Marine Engine Oil Resources and Information

PartsVu.com is happy to offer a wide selection of certified Mercury lubricants and marine engine oil to match the exact specifications of your Mercury outboard engine. If you need assistance servicing your Mercury outboard, 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, 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

Mercury Precision Lubricant and Engine Oil 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.

How do I change my Mercury 2-stroke outboard engine oil?

Engine oil selection is critical to long life, so review the information in your owner’s manual to make certain you are using the correct products. Not all TCW3 oils are formulated the same, and different Mercury models do prefer specific oils. Mercury Marine offers a wide assortment of engine oil – both in blend and additives. If you are uncertain exactly which oil is best for your application, consult your owner’s manual.

If you do locate contamination in the oil tank, use a vacuum extractor to pull the remaining oil out of the tank for proper disposal. While good quality two-stroke oil is certainly expensive, running contaminated oil can lead to catastrophic failure. If you have never cleaned the bottom of your tank, prepare to be surprised by what you find.

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.

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 check the hours on my Mercury outboard motor?

To access a Mercury outboard’s computer memory, you will need to visit an authorized Mercury outboard dealer. The dealer will have the necessary computer software and the cable to plug the shop’s laptop into your outboard.

A dealer might charge you for 30 minutes or so of labor to run a diagnostic scan, but if you are buying a used Mercury outboard motor, this investment is well worth it. However, if you are negotiating to buy the motor from a dealer, the dealer should be glad to give you a diagnostics report for no charge.

To access a Mercury outboard’s computer memory, you will need to visit an authorized Mercury outboard dealer. The dealer will have the necessary computer software and the cable to plug the shop’s laptop into your outboard.

A dealer might charge you for 30 minutes or so of labor to run a diagnostic scan, but if you are buying a used Mercury outboard, this investment is well worth it. However, if you are negotiating to buy the motor from a dealer, the dealer should be glad to give you a diagnostics report for no charge.

How many hours will a Mercury outboard last?

Why all of the discussion about Mercury outboard engine hours? The question of how many hours a Mercury outboard is expected to last is at the heart of the matter. Whether you are trying to plan how long before you probably have to buy a new outboard or working to determine the fair value for either a used outboard you are selling or considering purchasing, projecting how long engines last is critical.

The question of how long a Mercury outboard will last includes a lot of “it depends.” The reality is, a well-maintained Mercury outboard will last a long, long time. Also, even with proper maintenance, some types of engine usage are just harder on the engine. For example, if a Mercury outboard experiences long periods of wide-open throttle, extended periods of trolling, or load weight is commonly higher than recommended, service intervals need to be more frequent, and overall engine life will likely be shorter.

Is changing oil on Mercury outboard engines the same as changing oil lower unit Mercury outboard engines?

No, changing the oil in the lower unit of a Mercury outboard engine is not the same as changing the engine oil. The lower unit, also known as the gearcase or gearbox, contains the gears and bearings that transfer power from the engine to the propeller.

To change the oil in the lower unit of a Mercury outboard engine, you will need to follow a separate set of steps and use specific oil designed for this purpose. This oil is different from the engine oil and is formulated to protect the gears and bearings from wear and corrosion.

To change the oil in the lower unit of a Mercury outboard engine, you will typically need to remove the drain plug, drain the old oil, and then refill the gearcase with new oil using a special oil pump. The procedure may vary depending on the specific model and year of the engine, so it is important to consult the manufacturer's instructions or seek advice from a certified dealer or technician.

In contrast, changing the engine oil involves draining the old oil from the engine crankcase, replacing the oil filter, and refilling the engine with new oil. This procedure is typically simpler and more straightforward than changing the oil in the lower unit, but it is still important to follow the manufacturer's recommendations and use the correct type and amount of oil for your engine.

What's the best 4 stroke oil Mercury outboard engines operating in cold weather?

For Mercury outboard engines operating in cold weather, it is recommended to use a 10W-30 or 5W-30 marine oil with a synthetic blend or full synthetic formula. These types of oils have better low-temperature flow characteristics and are less prone to thickening in cold temperatures, which can cause engine damage. Some recommended oils for cold weather use in Mercury outboard engines include Quicksilver 25W-40 Synthetic Blend 4-Stroke Marine Oil and Mercury 4-Stroke Outboard Oil SAE 10W-30. It's important to consult the owner's manual for specific oil recommendations for your engine.

Where can I learn more about Mercury Outboard Engine Oil?

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 Mercury engine oil maintenance.

To get you off to a good start, these are some of the most important articles on Mercury outboard lower unit oil, Mercury outboard oil maintenance, and more:

• Guide to Mercury Marine Precision Oils & Lubricants
• Mercury 4-Stroke Oil Change - 100-hour Service
• Mercury 2-Stroke Oil Change - 100-hour Service
• Mercruiser Oil Change In 8 Easy Steps

Does changing oil in Mercury 115 outboard engines take longer as the engine ages?

It's generally not the case that changing oil in a Mercury 115 outboard takes longer as the engine ages. However, the frequency of oil changes and the difficulty of accessing the oil filter may change over time as the engine and its components wear and experience normal wear and tear.

The recommended frequency of oil changes for a Mercury 115 outboard can vary depending on factors such as the engine model year, operating conditions, and maintenance history. However, in general, it is recommended to change the oil and oil filter every 100 hours of operation or annually, whichever comes first.

As an engine ages, it may experience wear and tear on various components, including gaskets, seals, and other parts that may make it more difficult to access and change the oil filter or drain plug. Additionally, as the engine accumulates more hours of operation, it may become more prone to sludge buildup or contamination, which may require additional time and effort to clean or flush out.

Overall, the time required to change the oil in a Mercury 115 outboard may vary depending on factors such as the engine age, maintenance history, and operating conditions, but should generally not increase significantly with age. It is important to follow the manufacturer's recommended maintenance schedule and procedures to ensure the engine continues to perform reliably and efficiently over time.

What's the shelf life of most Mercury outboard lubricants?

The shelf life of most Mercury outboard lubricants is typically around 3-5 years when stored properly in a cool, dry place and in their original, unopened containers. However, it's important to check the expiration date on the container or consult the product's technical data sheet for specific information on the product's shelf life.

Once opened, the shelf life of the lubricant may be shorter due to the potential for contamination from moisture or other impurities. It's important to store opened lubricants in airtight containers and to use them within a reasonable amount of time to ensure optimal performance and protection for your outboard engine. It's also a good idea to mark the date that the container was opened on the container itself for reference.

What happens if I skip Mercury outboard steering cable lubrication as part of my annual maintenance?

Skipping Mercury outboard steering cable lubrication as part of your annual maintenance can cause several issues with your boat's steering system. Over time, the steering cable can become stiff and difficult to turn, which can make it harder to steer the boat and potentially lead to unsafe operating conditions. This can also cause excess wear and tear on the steering components, which can result in costly repairs or even complete steering failure if left untreated.

What oil to use in Mercury 4 stroke outboard?

Mercury recommends using their own brand of 4-stroke outboard oil in their engines. This oil is specially formulated to provide optimal protection and performance for your engine. Using other brands of oil may not provide the same level of protection and could potentially cause damage to your engine.

What is the "W" in oil?

The "W" in oil stands for "winter" and refers to the oil's viscosity in cold temperatures. The lower the number before the "W", the better the oil will perform in cold temperatures.

What is 4-stroke oil?

4-stroke oil is specially formulated for use in 4-stroke engines. It is designed to provide the necessary lubrication and protection for the engine's internal components, including the piston, crankshaft, and bearings.

How to add oil to Mercury outboard 2 stroke?

To add oil to a Mercury 2-stroke outboard, first remove the oil fill cap located on the top of the engine. Then, using a funnel, slowly pour the recommended type and amount of oil into the oil fill opening until the oil level reaches the upper mark on the dipstick. Be sure not to overfill the engine with oil.

How to bypass oil injection on Mercury outboard? 

Bypassing the oil injection system on a Mercury outboard is not recommended, as doing so can cause damage to the engine. If you are experiencing issues with the oil injection system and believe that you need to bypass oil injection, Mercury outboard technicians can perform the job or offer better solutions - especially if your outboard has other serious issues.

How often to change oil in Mercury 4 stroke outboard?

Mercury recommends changing the oil in their 4-stroke outboard engines every 100 hours of use or once per year, whichever comes first. However, if you operate your engine in harsh conditions, such as saltwater or dusty environments, more frequent oil changes may be necessary.

Best fuel additive for Mercury outboards?

There are many fuel additives available on the market that are compatible with Mercury outboards. The best one for your engine will depend on your specific needs and the conditions in which you operate your boat. Some popular options include stabilizers to keep fuel fresh, cleaners to remove deposits from the fuel system, and octane boosters to increase performance.

Additives to help compression in a Mercury outboard?

While there are no additives that can directly increase compression in an outboard engine, there are some that can help to improve overall engine performance. These include fuel system cleaners to remove deposits from the combustion chamber, oil additives to reduce friction and wear on internal engine components, and octane boosters to improve combustion efficiency. It's important to use additives that are specifically designed for use in outboard engines and to follow the manufacturer's recommendations for use.

What info does a Mercury outboard oil filter chart provide boaters?

A Mercury outboard oil filter chart provides boaters with important information about compatible oil filters that can be used with their Mercury outboard engines. The chart typically includes the part numbers for different oil filters that are compatible with specific Mercury outboard engine models and sizes.

The chart may also provide additional information about the oil filter, such as its dimensions, filtration rating, and recommended replacement interval. This information can help boaters choose the correct oil filter for their engine and ensure that it provides the necessary level of protection against contaminants that can cause engine damage or wear.

What's the difference between Mercury 5.7 engine oil and Mercury MerCruiser 3.0 engine oil?

The main difference between Mercury 5.7 engine oil and Mercury MerCruiser 3.0 engine oil is their viscosity or thickness. Viscosity is a measure of how easily oil flows at a certain temperature, and different engines may require different viscosities depending on their design and operating conditions.

Mercury 5.7 engine oil is designed for use in Mercury's 5.7-liter inboard engines and is typically available in a range of viscosities, including 10W-30 and 20W-40. This oil is formulated to provide protection against wear, deposits, and corrosion, and to maintain its performance in a variety of conditions, including high temperatures and heavy loads.

Mercury MerCruiser 3.0 engine oil, on the other hand, is designed for use in MerCruiser's 3.0-liter inboard engines and is typically available in a single viscosity, such as 25W-40. This oil is also formulated to provide protection against wear, deposits, and corrosion, but may have slightly different additives and properties than the Mercury 5.7 engine oil to better suit the specific needs of the MerCruiser 3.0 engine.

Overall, it is important to use the recommended type and viscosity of oil for your specific engine to ensure optimal performance and protection. Consult the manufacturer's recommendations or seek advice from a certified dealer or technician to determine the correct oil for your engine.