See how AMSOIL products perform in the lab and in the field.

Throttle Response and Engine Performance

Marine engine oil

High RPM Marine Engine

Marine engine oil is constantly under load. AMSOIL manufactures high rpm marine engine oil for 4-cycle water cooled (*NMMA FC-W) engines. Our customers find better throttle response and overall engine performance.

The typical marine engine will run about 5000 rpm at 30 mph compared to an automobile engine that runs at about 2000 rpm at 60 mph. Unlike an automobile engine that eases its load with coasting or downhill travel a marine engine rarely coasts. High heat and high rpm can easily break down the oil’s viscosity causing it to become thinner. Thinner oil can no longer separate moving parts from wear and friction. AMSOIL’s extreme film strength resist viscosity shear for longer lasting lubrication of moving parts eliminating metal to metal contact. Engines run quieter and perform their best so you get the most power and performance from you engine all season long. For high-rpm running engines, AMSOIL keeps inboard/ outboard engines and personal watercraft engines running their best.

*AMSOIL 4-stroke oil for marine engines are certified by the National Marine Manufacturers Association (NMMA), meeting the requirements of Four Cycle – Water-cooled (NMMA FC-W) Catalyst Compatible specification, which is backward-compatible with the FC-W specification.

Question for marine engine oilOur customers ask: “My Mercury owner’s manual specifies a synthetic-blend, which AMSOIL products should I use?

AMSOIL Technical: “Mercury’s owner’s manual discourages the use of full-synthetic and most owners will not consider straying from these guidelines. So AMSOIL designed a product for these customers known as “WCM” Marine synthetic-blend Engine Oil SAE 25W-40.

4-Stroke 10W30 Marine

Customer Review

10W-30 marine

4-Stroke 10W-40 Marine

Customer Review

10w-40 marine

4-Stroke 25W-40 Marine
synthetic blend (WCM)

Customer Review

25W-40 marine

Diesel Marine
10W-40 (AME)

Customer Review

diesel marine

Black Finish
Oil Filter (EaOM)

Customer Review

Black motorcycle filter

Chrome Finish
Oil Filter (EaOMC)

Customer Review

Chrome motorcycle filter

Marine Outboard

AMSOIL Lookup Guides
Find Oil filters and other specialized products
for your marine engine

Boaters See Less Exhaust and More Throttle Response

Direct fuel injection (DFI) run leaner oil mix ratios to improve combustion efficiency and reduce exhaust emissions to meet EPA (Environmental Protection Agency) standards. However, these leaner gas-to-oil ratios means less oil available to provide the necessary oil film strength on cylinder wall and bearings to prevent scuffing and wear. Another problem is the degree to which a 2-stroke oil burns off. Unburnt oil leaves deposits on spark plugs, piston rings and plug exhaust ports. These deposits accumulate faster when idling or trolling the engine for any length of time. Excessive buildup is noticed with delayed throttle response, rough engine noise or excessive exhaust smoke when the engine is throttled up to max speed again. Over time these deposits become solid causing unnecessary engine wear and reduce the engine’s overall power and performance.

AMSOIL solves these problems with its extremely high oil film strength and cleaner burning gas-to-oil fuel ratio. These 2-cycle marine oils are formulated to provide the highest oil film strength with leaner oil mix ratios compared to other leading brands. The oil burns cleaner to eliminate the problems of plug fouling, ring sticking and reduce exhaust smoke beyond EPA standards. Customers choose AMSOIL because they realize consistent throttle response and dependable engine starts. Even after prolonged idling or trolling, engines reach maximum rpm without hesitation. Oils are formulated with quality additives to provide superior oil film strength eliminating metal to metal contact and burn clean to eliminate deposit buildup. AMSOIL delivers the extra power and performance enthusiasts expect from their engine.

AMSOIL marine lubricants engineered with advanced technology specifically for marine two-stroke engine applications. Use the oil as per-mix fuel, or as direct fuel injection for marine engines with factory-lean setting.

AMSOIL Technical questionOur customers ask: “Can I use AMSOIL HP Marine Synthetic 2-Stroke Oil in my Evinrude® E-TEC™ at the factory-lean setting?”

AMSOIL Technical: “Yes. HP Marine is excellent for Evinrude® E-TEC™ factory-lean setting. HP Marine (HPM) can be used in place of Evinrude XD100™ brand 2-Cycle Oil.”

2-Stroke HP Marine

Customer Review

25W-40 marine

2-Stroke Marine Injector
Oil (AIO)

Customer Review

2-stroke injector oil

2-Stroke 100:1 Marine
Pre-Mix (ATO)

Customer Review

100 to 1 premix

Marine Gear Lube
75W-90 (AGM)

Customer Review

marine gear lube

Water Resistant Grease

Customer Review

Water resistant grease

Powersports Coolant

Customer Review

Powersport Coolant


Customer Review


Gasoline Stabillizer

Customer Review

gasoline stabillizer
Powersport and racing catalogue

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Marine and Personal Watercraft
Powersports and Racing

last update June 1st, 2021
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