Marine Engine & Gear Lubricants — Oils, Greases & Fluids for Reliable Performance

Marine engine and gear lubricants are specially formulated oils and greases designed to protect internal combustion engines, gearcases, sterndrives, transmissions, and marine components from wear, corrosion, heat, and water contamination. These products help ensure smooth operation, extend service life, and maintain peak performance in demanding saltwater, freshwater, and high-load conditions. Unlike automotive lubricants, marine formulations incorporate additives that resist moisture, foaming, rust, and shear under continuous operation.

Types of Marine Engine & Gear Lubricants

Marine Engine Oils

Engine oil lubricates internal components, reduces friction, and carries heat away from moving parts.

• 2-Stroke Engine Oils – Designed for fuel-mixed outboards, optimized for combustion and minimal deposits

• 4-Stroke Engine Oils – For modern four-cycle outboards, sterndrives, and inboards

• Synthetic Marine Oils – Enhanced thermal stability, shear resistance, and extended drain intervals

Marine engine oils are engineered to withstand higher loads and moisture exposure compared to automotive oils.

4-Stroke Engine Oil

West Marine offers 4-stroke engine oil for gasoline and diesel engines. Choices include non-synthetic, synthetic blends and full-synthetic motor oils. Extremely popular are Chevron’s line of Delo motor oils, Shell ROTELLA® motor oil and Quicksilver, West Marine and Sierra motor oils. Motor oils are offered in a range of viscosities.

2-Cycle Motor Oil

You will find a selection of premium, non-synthetic and synthetic blend TC-W3 2-cycle oil for outboards and PWCs. Special formulations are offered for high-performance DFI outboards. Choices include West Marine, Quicksilver, Sierra and Evin-Johnson brands.

Marine Gear Oils & Sterndrive Lubricants

Gear oil protects lower unit gears, bearings, and seals from wear and corrosion.

• Marine Gearcase Oil – For sterndrive and outboard lower unit gearcases

• Hypoid Gear Oils – For heavy-duty gear protection

• Synthetic Gear Lubricants – Better thermal protection and extended life

These products ensure smooth gear engagement, quiet operation, and protection against water intrusion that can cause rapid degradation.

Greases for Marine Applications

Grease provides lubrication to moving parts that oil alone cannot reach.

• Water-Resistant Grease – For steering linkages, fittings, and anchor winches

• EP (Extreme Pressure) Grease – For high-load bearings and mechanical systems

• Synthetic Grease – Enhanced performance in temperature extremes

Marine greases resist washout from water and maintain lubrication under heavy loads and vibration.

A variety of pumps make changing engine oil or gear lube easy.

If you prefer to change your boat’s engine oil yourself and are tired of busting your knuckles in the confined space under your boat’s engine, we suggest you consider a manual or electric oil change pump. Some models of oil change pumps are designed to extract engine oil out through an engine’s dip stick tube, while others can be plumbed directly to the engine’s oil sump drain hole.

Apart from changing the crankcase oil in your marine engine, the gear oil in the lower unit of outboards and inboard/outboard engines must also be periodically changed. For this, West Marine offers several lower unit manual gear lube pumps to make the process easy.

Why Marine-Specific Lubricants Matter

Marine engines and gearboxes operate under conditions generally harsher than automotive applications:

• Continuous high RPM loads

• Saltwater and freshwater exposure

• Higher humidity and moisture intrusion

• Thermal cycling and heat soak

• Propulsion system stresses

Marine lubricants incorporate corrosion inhibitors, anti-foam agents, and water-shedding additives to maintain protection under these conditions.

Oil Filters

West Marine offers spin-on oil filters for use in most makes and models of outboard motors and marine engines. Brands carried include Quicksilver, Sierra, Yamaha and Yanmar.

Choosing the Right Lubricant by Engine Type

Outboard Engines

• Requires oils compatible with high RPM, frequent load changes

• Many models require oils formulated for fuel-mixed or oil-injection systems

Inboard & Sterndrive Engines

• SAE viscosity and additive packages matched to cooling and load profiles

• Gearcase oils selected per manufacturer specification

High-Performance Engines

• Premium synthetic oils help reduce wear and support peak horsepower

• Keep seals and pumps operating smoothly under stress

Protect and extend the life of moving parts with marine grease.

West Marine offers several types of multi-purpose marine grease for lubricating outboard tilt tubes, shift and throttle linkages, trailer bearings and other moving parts. Grease can be purchased in tubes or in cartridges that are designed to fit into grease guns which are also offered.

Viscosity Grades & Performance Ratings

Correct viscosity ensures proper film strength and thermal behavior.

• SAE 10W-30 / 10W-40 – Standard marine engine oil grades

• SAE 30 / 40 – Common for sterndrives and specific engines

• API / NMMA Certified – Assurance of tested marine performance

Viscosity and certification ensure proper protection across temperature ranges.

Oil Change & Drain Intervals

Proper maintenance intervals help prevent premature wear.

• Service marine oil at recommended hour marks

• Replace gear oil per manufacturer interval

• Check seals and water intrusion when servicing

• Document service history for reliability

Regular oil changes decrease buildup and help maintain peak performance.

Additives & Performance Enhancers

Some formulations include:

• Anti-wear agents

• Shear stabilizers

• Corrosion inhibitors

• Detergents and dispersants

• Seal conditioners

Additives help maintain engine cleanliness, protect bearings, and extend component life.

Storage & Winterization Fluids

Proper protection during off-season storage prevents internal corrosion.

• Rust inhibitors for engines and gearcases

• Stabilized oils for long-term lay-up

• Fogging oils for internal combustion protection

Seasonal treatment helps prevent oxidation and degradation during winter months.

Environmental & Safety Considerations

• Follow disposal guidelines for used oil and gear fluids

• Choose biodegradable options where appropriate

• Wear protective gear when handling and changing fluids

• Avoid release of contaminants into waterways

Responsible handling protects both boat systems and the marine environment.

How Much Lubricant You Need

Total fluid requirements depend on:

• Engine model and displacement

• Gearcase or sterndrive size

• Auxiliary systems (generators, pumps)

Service manuals provide exact specifications for capacity.

Maximize Performance and Longevity with Quality Lubricants

Marine engine and gear lubricants play a crucial role in dependable operation and long-term protection. Whether performing routine maintenance, preparing for seasonal storage, or outfitting a high-performance vessel, selecting the right oils, greases, and fluids ensures smooth operation, reduces wear, and extends the life of your marine powertrain.