MerCruiser Fuel & Oil 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.

What type of fuel can I use?

IMPORTANT: Use of improper gasoline can damage your engine. Engine damage resulting from the use of improper gasoline is considered misuse of the engine and will not be covered under the limited warranty.  Consult your specific Operation, Maintenance & Warranty manual for more details.

NOTICE: Running out of fuel can damage catalyst components. Do not allow the fuel tanks to become empty during operation of catalyst engines. Consult your specific Operation, Maintenance & Warranty manual for more details.

2001 models and newer Mercury MerCruiser engines beginning with serial number 0M300000 will operate satisfactorily when using a major brand of unleaded fuel meeting the following specifications:

  • USA and Canada - Have a posted pump Octane Rating of 87 (R+M)/2 minimum. Premium gasoline [92 (R+M)/2 Octane] is also acceptable. Do not use leaded gasoline.
  • Outside USA and Canada - Have a posted pump Octane Rating of 90 RON minimum. Premium gasoline (98 RON) is also acceptable. If unleaded gasoline is not available, use a major brand of leaded gasoline .

Consult your specific Operation, Maintenance & Warranty manual for more details.

Use the following chart to determine correct fuel for engines prior to 2001

Model  

Gasoline  

Additives  

1987 through 2000 : V8 350 cid, Except EFI Models. (Note 1)

1990 through 2000: 4 Cyl 181 cid, V8 454, & 502 cid, Except EFI Models. (Note 1)

1991 & 2000: V8 540 & 572 cid, Except Supercharged Models.

US/CAN - 87 (R+M)/2 98 RON minimum octane major brand of unleaded regular or premium without alcohol (Notes 2 & 3)

NON US/CAN - 90 RON minimum octane major brand of unleaded regular or premium without alcohol (Notes 2, 3 & 4)

None Required

EFI: V8 350,454 & 502 cid. (Note 5 provides requirements for specific serial numbers)

US/CAN - 87 (R+M)/2 minimum octane unleaded regular or premium without alcohol, DO NOT USE Leaded Gasoline (Notes 2 & 3)

NON US/CAN - 90 RON minimum octane major brand of unleaded regular or premium without alcohol (Notes 2, 3 & 4)

None Required

V6 and All Other Older 4, 6 Cyl & V8 Models, Except Supercharged Models. (Note 1)

US/CAN - 87 (R+M)/2 minimum octane unleaded regular or premium without alcohol, DO NOT USE Leaded Gasoline (Notes 2 & 3)

NON US/CAN - 90 RON minimum octane major brand of unleaded regular or premium without alcohol (Notes 2, 3 & 4)

A good-grade automotive valve lubricant

Black Scorpion models

Serial numbers 0L005600 and below - DO NOT USE Leaded Gasoline

US/CAN - 91 (R+M)/2 minimum octane unleaded regular or premium without alcohol (Notes 2 & 3)

NON US/CAN - 98 RON minimum octane major brand of unleaded regular or premium without alcohol

Serial numbers 0L005601 and above - DO NOT USE Leaded Gasoline

US/CAN - 87 (R+M)/2 minimum octane unleaded regular or premium without alcohol (Notes 2 & 3)

NON US/CAN - 90 RON minimum octane major brand of unleaded regular or premium without alcohol

None Required

Supercharged Models

US/CAN - 92 (R+M)/2 minimum octane Unleaded premium without alcohol, DO NOT USE Leaded Gasoline (Notes 2 & 3)

NON US/CAN - 98 RON minimum octane Unleaded premium without alcohol (Notes 2, 3 & 4)

None Required

Notes:

1. The cylinder heads on these engines have hardened exhaust valve seat inserts.

2. If gasoline with alcohol must be used, periodically inspect complete fuel system for leaks and do not store fuel in boat's fuel tank for long periods of time.

3. To increase valve life on all MerCruiser engines, the following recommendations should be considered:

  • Use a propeller that allows engine to operate at or near the top of its maximum RPM range when at full throttle with a normal boat load
  • Operation at 3/4 throttle setting or lower is recommended. Refrain from prolonged operation at maximum (full throttle) RPM

4. If unleaded gasoline is not available, use a major brand of leaded gasoline.

5. MCM 5.7L Alpha or Bravo EFI: Serial number 0F415136 and Below
MCM/MIE 454 & 502 Magnum Stern Drive or Ski EFI: Serial number 0F417515 and Below
MIE 350 Magnum Ski EFI: Serial number 0F350545 and Below.
USE 87 (R+M)/2 or 90 RON minimum octane Unleaded REGULAR Gasoline Without Alcohol. DO NOT USE Premium Gasoline. (Note 2)

Can I use reformulated or oxygenated fuels?

Reformulated (oxygenated) gasolines are required in certain areas of the USA and are acceptable for use in your Mercury MerCruiser engine. The two types of "oxygenates" used in these fuels are alcohol (ethanol) and ether (MTBE or ETBE). If the gasoline in your area contains either methanol (methyl alcohol) or ethanol, be aware of possible adverse effects. These adverse effects are more severe with methanol and worsen according to the percentage of alcohol in the fuel.  Alcohol in gasoline can absorb moisture from the air, causing the water and the alcohol to separate from the gasoline in the fuel tank.  For more detailed information, see the Ethanol FAQs under “MerCruiser Frequently Asked Questions”.

IMPORTANT:  The fuel system components in your MerCruiser engine will withstand up to 10% alcohol content in the gasoline. We do not know what percentage your boat’s fuel system will withstand. Contact your boat manufacturer for specific recommendations on your boat’s fuel system components (fuel tanks, fuel lines, and fittings).

Be aware that gasoline containing alcohol may cause increased:

  • Corrosion of metal parts
  • Deterioration of rubber or plastic parts
  • Fuel permeation through rubber fuel lines
  • Starting and operating difficulties

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.