Mercury Outboard Carburetors & Components

Mercury Marine Engine Carburetors and Components Resources and Information

PartsVu is happy to offer a wide selection of certified Mercury outboard carburetors and components for your Mercury outboard engine. In addition to marine carburetors, you can also shop gasket sets, fuel pump diaphragms, and convenient carburetor repair kits to perform maintenance on your Mercury outboard carburetor without having to spend money at the mechanic.

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

• Mercury Outboard Specs & Capacities Chart
• Mercury Outboard Serial Number Lookup
• Mercury Outboard Engine Schematics

Mercury Outboard Carburetors & Components FAQs

How does an Mercury outboard engine carburetor work?

Your Mercury outboard carburetor serves the essential function of mixing air and fuel in the exact right amounts to allow combustion within your outboard engine. This process is achieved through several components of the carburetor working in tandem. The choke plate allows or restricts airflow into the carburetor, while the throttle plate controls the amount of fuel. On the side of the carburetor is the throttle connection which manipulates the throttle plate, thus controlling the acceleration of your engine via the accelerator pump.

How do I service my Mercury 4-stroke outboard fuel system?

Use a filter wrench to loosen the existing filter element and use caution when removing it as it will be filled with gasoline. A clear plastic or glass container is helpful to dump the filter and examine the contents. A small amount of debris is common, as is a small amount of water after the fuel has had a moment to settle. More significant amounts of water would warrant further investigation.

Move back to the engine and locate the filter element(s) on the engine. The scope of this service will only include the low-pressure fuel filter and fuel water separator if applicable by model. Mercury recommends that owners do not service their high-pressure fuel filters. Depending on your engine model, the water separator filter (or castle filter) may be removed by using a wrench, standard tools, and a little caution. Unplug the water-in-fuel sensor if applicable and spin the cap off of the housing. Replace the filter element with a fresh one, lube the o-ring with grease or oil, and carefully reinstall the cap.

Locate your Mercury engine’s primer bulb if applicable and use the primer to pump up the fuel system. You should feel and hear gasoline entering and filling the filter cup. Check for leaks and prime until the bulb becomes firm.

If you are not already regularly running Mercury Quickare and/or Quickleen through your Mercury fuel system, the 100-hour service interval is an excellent time for a “shock treatment.” Quickare is a fuel system cleaner and top-lube that will help to clean deposits from the tank, lines, carburetors, injectors, and pumps. It breaks up fuel system varnish and will help to prevent gumming.

Quickleen is a fuel system conditioner that also helps to remove carbon deposits. The standard dose is one ounce per ten gallons, but if you are not running the product regularly, you can double that ratio for more cleaning power. Pour the products into the fuel tank fill and run the boat. No additional work is needed. It is a great idea to inspect your fuel tank fill’s o-ring for damage when you add fuel or additives as a damaged o-ring can allow water from rain or boat washing into your fuel system.

How do I perform an oil change on my Mercury 2-stroke outboard motor?

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 perform an oil change on my Mercury 2-stroke outboard motor?

Spent engine oil can be removed from the engine by extraction or via the oil pan drain screw plug. The extraction method requires the use of a vacuum extractor which is inserted down the dipstick tube and uses suction to pull the spent oil from the pan. Oil extraction tends to be very clean and is probably the most widely used among marine technicians. Alternatively, the drain screw itself can be removed. Be sure to have plenty of drain pan capacity as some engines can hold up to seven quarts of oil. We also recommend an oil absorbent pad like the 3M HP156 pad to catch any errant drips that might soil your driveway or lawn.

In cold climates, it may be helpful to start and warm the engine before draining the oil to thin it slightly. However, if possible, perform the engine oil change as the first part of the service since the maximum amount of oil will be in the oil pan already from the engine sitting allowing you to extract as much old oil as possible to minimize contamination of your fresh 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.

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.

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.

What's the difference between a 15 hp Mercury outboard 2 stroke carburetor and a 15 hp Mercury outboard 4 stroke carburetor?

The main difference between a 15 hp Mercury outboard 2 stroke carburetor and a 15 hp Mercury outboard 4 stroke carburetor is the way they deliver fuel to the engine. A 2 stroke carburetor mixes fuel and oil together in a specific ratio before delivering it to the engine, while a 4 stroke carburetor delivers only fuel to the engine.

Another key difference is that 2 stroke carburetors tend to be simpler in design and have fewer moving parts than 4 stroke carburetors. This can make them easier to maintain and repair, as well as more affordable. However, 4 stroke carburetors are typically more fuel efficient and produce fewer emissions than 2 stroke carburetors.

When it comes to performance, 4 stroke carburetors typically have a smoother and quieter operation than 2 stroke carburetors. They also tend to have more torque at lower RPMs, which can make them ideal for applications like trolling or slow-speed cruising. However, 2 stroke carburetors can offer higher top-end speeds and acceleration, making them a popular choice for racing or high-performance boating. Ultimately, the best carburetor for a specific application will depend on factors like boat size, usage, and personal preference.

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 Mecury marine engine maintenance.

To get you off to a good start, these are some of the most important articles on Mercury Carburetors, Mercury Carburetor Parts, and more:

• How To Protect Your Mercury Outboard
• Mercury Mercruiser Inboard Maintenance
• Winterizing Mercury Outboard Motor
• 7 Reasons Your Outboard Will Not Throttle Up and How ...

What is a carburetor and how does it work in a Mercury outboard engine?

A carburetor is a component in a Mercury outboard engine that mixes fuel and air in the correct ratio for combustion. It works by using a series of jets, needles, and other components to regulate the flow of fuel and air into the engine.

How do I know if my Mercury outboard carburetor needs to be cleaned or replaced?

Signs of a dirty or clogged carburetor in a Mercury outboard engine include hard starting, rough idling, poor acceleration, and decreased fuel efficiency. If these issues persist despite basic maintenance, it may be time to clean or replace the carburetor.

Can I clean my Mercury outboard carburetor myself or do I need a professional to do it?

It is possible to clean your Mercury outboard carburetor yourself with the right tools and knowledge, but it can be a delicate and time-consuming process. If you are not experienced with engine maintenance, it may be best to have a professional handle the cleaning or replacement.

What is a carburetor rebuild kit for a Mercury outboard engine?

A carburetor rebuild kit for a Mercury outboard engine includes all the necessary components to rebuild a damaged or worn carburetor, including gaskets, o-rings, needles, and jets.

Can I use aftermarket carburetor parts for my Mercury outboard engine?

While it is possible to use aftermarket carburetor parts for a Mercury outboard engine, it is generally recommended to use genuine Mercury parts to ensure proper fit and function. Aftermarket parts may not meet the same quality and performance standards as genuine Mercury parts.

How often should I replace the carburetor in my Mercury outboard engine?

The carburetor in a Mercury outboard engine should be inspected and cleaned regularly as part of routine maintenance. Depending on the age and condition of the engine, the carburetor may need to be replaced anywhere from every few years to every 10 years or more.

What are some common components found in Mercury carburetors?

Some common components found in Mercury carburetors include the float, needle valve, throttle plates, jets, and accelerator pump.

Does Mercury Marine manufacture carburetors for their outboard engines?

Yes, Mercury Marine does manufacture carburetors for their outboard engines.

Can Mercury outboard carburetors be rebuilt?

Yes, Mercury outboard carburetors can be rebuilt with the proper tools and knowledge.

Are Mercury and Mariner outboard motors carbureted or fuel injected?

Both Mercury and Mariner outboard motors can be either carbureted or fuel injected, depending on the model and year.

How often should I clean or rebuild my Mercury carburetor components?

It is recommended to clean or rebuild Mercury carburetor components every few years or as needed, depending on the frequency of use and maintenance of the outboard motor.

What are the most popular late model Mercury outboard engine carburetors sold on PartsVu.com?

PartsVu stocks a complete catalog of Mercury outboard carburetors for all years and models of Mercury outboard engines and Mercury inboard engines. The following are the most popular brands that we keep in stock for our loyal customers:

• 1979 Mercury 40 hp outboard carburetor
• 1980 80 hp Mercury outboard carburetor
• 1983 Mercury 25 hp outboard carburetor
• 1983 Mercury 50 hp outboard carburetor
• 1984 Mercury 50 hp outboard carburetor
• 1985 25 hp Mercury outboard carburetor
• 1985 Mercury 35 hp outboard carburetor
• 1985 Mercury 35 hp outboard carburetor
• 1985 Mercury 50 hp outboard carburetor
• 1985 Mercury outboard carburetor
• 1986 25 hp Mercury outboard carburetor
• 1986 Mercury 35 hp outboard carburetor
• 1986 Mercury outboard carburetor
• 1987 25 hp Mercury outboard carburetor
• 1987 35 hp Mercury outboard carburetor
• 1987 35 hp Mercury outboard carburetor
• 1988 Mercury 35 hp outboard carburetor
• 1989 25 hp Mercury outboard carburetor
• 1994 Mercury 40 hp outboard carburetor
• 1996 25 hp Mercury outboard carburetor
• 2006 Mercury 9.9 4 stroke carburetor

What are the most popular models of Mercury outboard engine carburetors sold on PartsVu.com?

PartsVu stocks a complete catalog of Mercury outboard carburetors for models of Mercury outboard engines and Mercury inboard engines. The following are the most popular brands that we keep in stock for our loyal customers:

• Mercury 2.2 outboard carburetor
• Mercury 2.5 hp outboard carburetor
• Mercury 3.3 hp outboard carburetor
• Mercury 3.5 hp outboard carburetor
• 4 hp Mercury outboard carburetor
• 7.5 hp Mercury outboard carburetor
• 9.8 hp Mercury outboard carburetor
• 9.9 Mercury outboard carburetor
• Mercury 15 hp outboard carburetor
• 18 hp Mercury outboard carburetor
• 20 hp Mercury outboard carburetor
• 25 hp 4 stroke Mercury outboard carburetor 
• 35 hp Mercury outboard carburetor
• 40 hp Mercury outboard carburetor
• 50 hp Mercury outboard carburetor
• Mercury classic 50 carburetor
• Mercury 60 hp 2 stroke carburetor
• 75 hp Mercury outboard carburetor
• 60 hp Mercury outboard carburetor
• 90 hp Mercury outboard carburetor
• Mercury 115 hp outboard carburetor

Does a Mercury 2-stroke carburetor need to be replaced at a 300-hour service interval?

There is no set service interval for replacing the carburetor on a Mercury 2-stroke outboard engine. The carburetor may need to be replaced if it becomes damaged or if it is not functioning properly. However, regular maintenance and cleaning of the carburetor can help to prolong its lifespan and ensure that it is functioning correctly. It is recommended to refer to the engine's maintenance schedule in the owner's manual for specific maintenance requirements and intervals.

How to adjust Mercury outboard carburetors?

Adjusting the carburetors on a Mercury outboard engine is an important part of maintenance that ensures your engine is running at peak performance. Here are the steps to adjust the carburetors:

1. First, warm up the engine to operating temperature.
2. Turn off the engine and remove the cowling cover to access the carburetors.
3. Locate the idle speed adjustment screws on the carburetors and turn them clockwise until they touch the stop.
4. Turn the screws counterclockwise 1-1/2 turns to set the initial idle speed.
5. Start the engine and let it idle.
6. Use a tachometer to adjust the idle speed to the correct RPM.
7. Next, adjust the idle mixture screws on the carburetors. Turn the screws in clockwise until the engine starts to stall, then back out the screws counterclockwise 1/4 to 1/2 turn. Repeat this process for each carburetor.
8. After adjusting the idle mixture, turn off the engine and reinstall the cowling cover.

It's important to note that carburetor adjustments should only be made by someone with experience and the proper tools. If you're not comfortable making these adjustments yourself, it's best to take your engine to a professional.

What is a carburetor rebuild kit for a Mercury outboard engine?

A carburetor rebuild kit is a set of parts that are used to rebuild or repair a carburetor. It contains various gaskets, O-rings, seals, and other small parts that are required to rebuild a carburetor on a Mercury outboard engine.

When should I consider replacing the carburetor on my Mercury outboard engine?

If your Mercury outboard engine is experiencing issues related to poor fuel mixture, low power, or difficulty starting, it may be time to consider replacing the carburetor. A faulty carburetor can cause a variety of engine problems and negatively impact engine performance.

What is the purpose of a Mercury carburetor rebuild kit?

The purpose of a Mercury carburetor rebuild kit is to provide all the necessary parts to repair or rebuild a faulty carburetor on a Mercury outboard engine. It includes all the necessary components for a thorough and comprehensive repair.

What are the benefits of using a carburetor rebuild kit for my Mercury outboard engine?

Using Mercury carburetor rebuild kits for your Mercury outboard engine can save you time and money by allowing you to repair or rebuild your carburetor without having to purchase a new one. It can also ensure that your carburetor is functioning properly, which can improve engine performance and increase fuel efficiency.

Can I install a carburetor rebuild kit on my Mercury outboard engine myself?

While it is possible to install a carburetor rebuild kit on your Mercury outboard engine yourself, it is recommended that you have some mechanical knowledge and experience working on engines. If you are unsure or uncomfortable with the process, it may be best to have a professional mechanic install the kit for you.