MerCruiser Parts FAQs

How can I find my closest authorized MerCruiser dealer?

Authorized MerCruiser dealers in the United States and Canada can be found under Find a Dealer on this website.

Links to regions outside of the United States and Canada can be found on the Contact Us page.

How often should spark plugs be changed?

Every 300 hours or 3 years, whichever comes first.

Where can I find the part numbers for specific engine or sterndrive components?

This information is published in our Parts manuals or is available from authorized dealers. You may purchase a Parts manual online. You will need your engine serial number, and, if applicable, the sterndrive or transom serial numbers.

Where can I buy genuine Mercury Precision Parts and how much do they cost?

Mercury Precision Parts are sold only through authorized dealerships. Consult the yellow pages to locate a local dealership or use the Dealer Locator on this web site for an extended search. The Parts Catalog on this site will allow you to identify the parts required for your engine. An authorized dealer can provide you with the retail price of the parts.

What is the warranty on parts?

Genuine Mercury or Quicksilver Precision Parts carry a limited 12-month warranty against defects in materials and workmanship. For specific details, contact your local dealer.

Can consumers purchase parts, tools, or service manuals directly from Mercury?

Parts and tools are available only through authorized dealers. Service manuals, parts catalogs and Operation, Maintenance & Warranty manuals are available online. You could also order all literature through any authorized Mercury dealer. Please have your outboard or sterndrive serial number before placing the order.

Where can I get factory Service manuals, Parts manuals, or Operation, Maintenance & Warranty manuals?

You can order all available literature online. You could also order all literature through any authorized Mercury dealer. Please have your outboard or sterndrive serial number before placing the order.

Where do I find maintenance and lubrication information for my engine?

The Operation, Maintenance & Warranty manual outlines the typical maintenance and lubrication items. If your manual is missing or damaged, please order online or through any authorized Mercury dealer. Please have your outboard or sterndrive serial number before placing the order.

The dealer says my part is no longer available. What am I supposed to do? Do you have something that will work in place of it?

Mercury Marine makes every effort to provide service replacement parts as long as possible. Many times, older part numbers will supersede to a newer part number or a replacement kit. In some cases, service parts for older models are no longer available (NLA). If you have the part number for a particular part you need, first contact your local authorized Mercury dealer.  Your dealer can also look up NLA parts through their factory on-line site.  For NLA parts, you may also contact authorized dealer Sea Way Marine in Seattle, WA, at 1-800-332-0803 or 206-937-7373.

What type of oil should I use? Can I use synthetic oil?

Engine Oil

For optimum engine performance and maximum protection, use the following oil:

Application Recommended Oil
All MerCruiser engines Mercury MerCruiser Full-Synthetic Engine Oil, 20W-40, NMMC FC-W rated

IMPORTANT: Lubrication requirements for catalyzed engines differ from the requirements for non-catalyzed engines. Some marine-grade lubricants contain high levels of phosphorus, which can damage the catalyst system on MerCruiser engines. Although these high-phosphorus lubricants may allow acceptable engine performance, exposure over time will damage the catalyst. Catalysts damaged by lubricants containing high levels of phosphorus may not be covered by the MerCruiser Limited Warranty.

If Mercury MerCruiser Full-Synthetic, 20W-40 oils is unavailable, use the following lubricants, listed in order of recommendation. If you are servicing a catalyst engine, use these for short periods of time only.

  1. Mercury/Quicksilver 25W-40 Synthetic Blend, NMMA FC-W-rated 4-cycle MerCruiser oil
  2. Mercury/Quicksilver 25W-40, NMMA FC-W-rated 4-cycle MerCruiser oil
  3. Other recognized brands of NMMA FC-W-rated 4-cycle oils
  4. A good-grade, straight-weight detergent automotive oil according to the last row of the operating chart below.

NOTE: We do not recommend non-detergent oils, multi-viscosity oils (other than as specified), non-FC-W-rated synthetic oils, low-quality oils, or oils that contain solid additives.

This crankcase oil recommendation supersedes all previously printed crankcase oil recommendations for MerCruiser gasoline engines. The reason for this change is to include the newer engine oils that are now available in the recommendation.

Older Operation, Maintenance & Warranty manuals, Service manuals and other publications that are not regularly updated will not be revised to show this latest engine oil recommendation. Current Operation, Maintenance & Warranty manuals, Service manuals and other service publications that receive regular updates will receive this revised recommendation the next time they are updated.

Can you cross reference parts to Fram, GM, NGK, etc?

With the exception of spark plugs, we do not cross-reference parts. Approved alternate brand spark plugs are listed in the service manuals or Operation, Maintenance & Warranty manuals and include AC, Champion, and NGK.

What is the difference between auto and marine parts? Can I use auto parts on my engine?

Electrical, ignition, and fuel system components on MerCruiser engines are designed and manufactured to comply with U.S. Coast Guard rules and regulations to minimize risks of fire or explosion. Use of replacement electrical, ignition, or fuel system components, which do not comply to these rules and regulations, could result in a fire or explosion hazard and should be avoided. Also, many other components on MerCruiser engines are designed and manufactured differently from standard automotive parts. Marine engines operate at or near full-throttle for most of their lives. They are also expected to operate in both fresh and saltwater environments. These conditions require numerous special parts. Care should be exercised when replacing marine engine parts as specifications are quite different from those of the standard automotive engine.

Can I install aftermarket accessories like stabilizer "fins" to help my boat get on plane faster?

While these add-on devices may reduce the time it takes to get the boat on plane, they may also cause or contribute to abnormal or even unsafe handling of the boat and failure of the anti-ventilation plate. Using a product often referred to as a stabilizer fin is a modification of the gearcase that may change the manner in which the boat operates on the water. With the unit trimmed fully down (in or under), a reduction of the time necessary to get a boat on plane may result. However, some V-bottom boats using a stabilizer fin may exhibit a tendency to roll over far to one side as soon as planing occurs. The direction and degree of the roll will be dictated by prop rotation, weight distribution, and degree of trim under. The boat roll can cause passengers to be ejected. Trimming up or out can reduce or eliminate the roll. Because it is not possible to know how a given boat will respond to the use of such a product without thorough testing, Mercury cannot recommend that such products be used or not used. Also, use of these products may cause or contribute to the failure of the anti-ventilation plate on the gearcase. Failures caused, or contributed to, by modification are not covered by the limited warranty.

Is there a closed-cooling (fresh-water) kit available for my engine?

We offer closed-cooling kits for most MerCruiser engines. However, there are some newer products for which a kit is not yet available. Please check with your authorized MerCruiser dealer to determine if a kit can be ordered and, if so, what other components may be required along with the kit.

Can I leave my lower unit or sterndrive empty of lubricant over the winter?

We do not recommend leaving a lower unit or sterndrive empty during storage periods. An empty oil cavity may allow moisture to collect on the gears, bearings and shafts. Rust will form when the moisture reacts with the air, damaging the internal components.

Note: If water was present when draining the gear oil, the lower unit or sterndrive should be inspected by an authorized dealer.

How can I prevent the propeller from sticking onto the shaft?

We recommend a liberal coat of one of the following Mercury Precision or Quicksilver Marine Lubricants on the propeller shaft: Special Lubricant 101, 2-4-C Marine Lubricant, or Anti-Corrosion Grease. These lubricants are available from any authorized Mercury Marine dealer.

Note: Always use the correct mounting hardware and torque the propeller nut to the correct specifications. Verify the propeller tightness after 20 hours of operation. DO NOT operate the boat with a loose propeller.

Are older fuel lines prone to failure from ethanol-based fuels? What about gaskets?

During the 1980s, many rubber components for use in fuel systems were developed to withstand exposure to fuels containing ethanol. If rubber components in a fuel system are suspected to be of this vintage or older it may be advisable to replace them with newer ethanol-safe components before using fuels containing ethanol. Check with the manufacturer for advice or frequently inspect these fuel-system components for signs of swelling or deterioration and replace if problems are noted.

What should be done when storing boats with ethanol-blended fuels for extended periods?

Follow the instructions for normal storage preparation found in the Operation, Maintenance & Warranty manual. When preparing to store a boat for extended periods of two months or more, it is best to completely remove all fuel from the tank. If it is difficult or not possible to remove the fuel, maintaining a full tank of fuel with a fuel stabilizer added to provide fuel stability and corrosion protection is recommended. It is best to add the stabilizer and fuel treatment to the tank at the recommended dosage, run the engine for 10 minutes to allow the system to be cleaned, shut off the fuel valve to interrupt the fuel supply and allow the engine to run until it stops, and top off the tank until it’s full to reduce the amount of exchange with the air that might bring in condensation. Do not cap the tank vent and do not fill with fuel to the point of overflowing. Some extra space should be maintained in the tank to allow for expansion and contraction of the fuel with temperature changes. A partially full tank is not recommended because the void space above the fuel allows air movement that can bring in water through condensation as the air temperature moves up and down. This condensation could potentially become a problem.

Mercury Marine Quickstor can help maintain fuel systems in storage. It contains oxidation inhibitors to reduce oxidation and gum formation, metal-chelating agents to protect metal components from corrosion, water-absorbing agents to reduce the presence of free water, and dispersants to help suspend and disperse debris. When placing the boat back in service, be sure to reopen the fuel valve to the engine.