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SAE 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT)
SAE 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT) 10W30

AMSOIL 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT) is a premium quality synthetic formulation engineered for the harsh operating conditions of marine environments. It withstands the intense mechanical action of continuous, high RPM operation to deliver superior viscosity protection. Formula 4-Stroke® Marine Synthetic Motor Oil is specially fortified with a heavy treatment of advanced additives that protects motors against wear, rust and deposits. It excels in both high horsepower applications and all-day trolling conditions.

Package sizes include:

1-Quart Bottle
1-Quart Bottles (case of 12)
55-Gallon Drum

Product Code: WCT • Brand: AMSOIL




MSDS Data Sheet

Product Details Tech Data Reviews & RatingRelated Videos

Product Applications
AMSOIL Formula 4-Stroke® Marine Synthetic 10W-30 Motor Oil (WCT) is recommended for gasoline fueled four-stroke outboard, inboard, inboard/outboard (I/O) and personal watercraft motors. AMSOIL WCT motor oil is recommended for the following applications whenever an SAE 5W-30, 10W-30 or straight SAE 30 oil is called for:

Product Application Specs

Four-stroke outboard motors: Honda®, Mercury®, Yamaha®, Johnson®/Evinrude®, Bombardier/BRP®, Suzuki®, Nissan®, Tohatsu®

Inboard and I/O: Mercruiser®, Volvo Penta®, OMC®, Chrysler® Marine, Crusader®, Marine Power®, Chevrolet®, Ford®

Personal Watercraft: Honda®, Yamaha®, Bombardier/BRP® (Sea-Doo®), Polaris®

Note: AMSOIL Formula 4-Stroke® Marine Synthetic 10W-30 is recommended for use in place of 5W-30 as specified by Honda®.

NMMA FC-W • API SL

Product Description
AMSOIL 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT) is a premium quality synthetic formulation engineered for the harsh operating conditions of marine environments. It withstands the intense mechanical action of continuous, high RPM operation to deliver superior viscosity protection. Formula 4-Stroke® Marine Synthetic Motor Oil is specially fortified with a heavy treatment of advanced additives that protects motors against wear, rust and deposits. It excels in both high horsepower applications and all-day trolling conditions.

4-Stroke Outboard Motor Warranty Certified

Formula 4-Stroke® Marine Synthetic Motor Oil is certified by the National Marine Manufacturers Association (NMMA) for use in four-stroke outboard motors. This high quality oil demonstrates outstanding performance, exceeding the NMMA "FC-W" (Four Cycle-Water) specification requirements. Formula 4-Stroke® Marine Synthetic Motor Oil fulfills the warranty requirements of four-stroke outboard motor manufacturers.

• NMMA Registration #FB-30011B 10W-30

Superior Protection Against Engine Wear
Marine engines operate under high loads and RPMs for extended periods of time, causing traditional automotive oils to break down and lose viscosity. To ensure good protection, the NMMA set minimum shear stability requirements for FC-W. AMSOIL Formula 4-Stroke® Marine Synthetic Motor Oil greatly exceeds the FC-W shear stability requirements, outperforming competitive oils to deliver a superior lubricating film. Formula 4-Stroke® Synthetic Oil also contains robust anti-wear additives that further reduce wear in metal-to-metal contact regions (see Four-Ball Wear Test graph).

Four Ball Wear test

HTHS Viscosity
While automobile engines normally operate at around 2,500 rpm, outboard motors can run twice as fast, requiring greater levels of wear protection and better bearing durability than automobiles. In addition, prolonged idling and low operating temperatures contribute to fuel dilution, further thinning the oil. To ensure adequate protection for their engines, marine engine manufacturers set minimum high temperature/high shear (HTHS) viscosity limits. AMSOIL Formula 4-Stroke® Marine Synthetic Motor Oils are shear stable and formulated with sophisticated oil additive chemistry, exceeding the HTHS requirements of both the API and NMMA FC-W (see graph).

HTHS Viscosity

Service Life
• Four-stroke outboard motors and personal watercraft applications: Due to potential fuel dilution or water contamination, change oil at the engine or watercraft manufacturer recommended interval.

• Inboard and I/O applications: Change oil at two times the engine manufacturer recommended interval or one year, whichever comes first.

Mixing AMSOIL
AMSOIL Formula 4-Stroke® Marine Synthetic Motor Oil is compatible with conventional and synthetic motor oils. Mixing AMSOIL motor oils with other oils will, however, shorten the oil life expectancy and reduce the performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed.

Aftermarket oil additives are not recommended for use with AMSOIL motor oils.

HEALTH & SAFETY
This product is not expected to cause health concerns when used for the intended application and according to the recommendations in the Material Safety Data Sheet (MSDS).

Click here to view the MSDS Data Sheet for AMSOIL WCT.

Keep out of the reach of children. Don't pollute. Return used oil to collection centers.

TYPICAL TECHNICAL PROPERTIES
 AMSOIL FORMULA 4-STROKE® MARINE SYNTHETIC MOTOR OIL (WCT)
SAE 10W-30, API SL, NMMA FC-W
Kinematic Viscosity @ 100°C, cSt (ASTM D-445) 11.7
Kinematic Viscosity @ 40°C, cSt (ASTM D-445) 74.5
Viscosity Index (ASTM D-2270) 152
CCS Viscosity, cP @ (°C) (ASTM D-5293) 6032 (-25)
Flash Point °C (°F) (ASTM D 92) 236 (457)
Fire Point °C (°F) (ASTM D 92) 258 (496)
Pour Point °C (°F) (ASTM D 97) -48 (-54)
Noack Volatility, % weight loss (g/100g) (ASTM D-5800) 4.8%
Four Ball Wear Test (ASTM D 4172 @ 40 kgf, 150°C, 1800 rpm, 1 hour, Scar in mm) 0.40
Total Base Number (ASTM D-2896) 10.5
HTHS (cP) 3.64
Humidity Cabinet Rust (ASTM D-1748) Pass

AMSOIL Marine Oils are put to test in Evinrude E-Tec equipped rental boats

Did this product meet your expectations?

(click on a star to rate)
Product Name: SAE 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT)
Current Rating: 4.68 out of 5 stars
Total Votes: 14 vote(s)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Norman: space

My first boat. Amsoil is my only choice.

This is my first boat. It has a Yamaha 175hp SHO 4-Stroke. I have Amsoil in everything I own. After the breakin hours passed. I replaced everything with Amsoil. Motor,lower unit and bearing grease. It's the only oil for me. Always a Great choice.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by James: space

I buy this marine-specific synthetic oil.

I use this great lube oil for my 1990 Cruisers Esprit with twin Crusader 350's. I am never disappointed with this synthetic, even though they were designed for straight SAE 40. They run smooth and oil pressures are spot on.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Robert: space

The best oil I've used so fat

Fantastic no issues with this product will buy again and recommend it

Thanks

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Andres: space

Yes

Perfect oil

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Bryan: space

Great value

Great value

Item Reviewed: Formula 4 Stroke Marine Motor Oils

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Triston: space

I will buy this again

Great product, love it

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Russell: space

Oil

Use Amzoil in all my cars and motorcycles, jetski's etc.
Never had an oil related failure.
Will continue to trust Amzoil.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Robert: space

Great stuff

Great stuff. Boat runs way better.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Brian: space

Yes

Great product when two outboards cost 50k you use the best product possible. Please make filters for yamaha outboards

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Vic: space

Improved power

I recently started using Amsoil Marine in our Yamaha Jet Boat. With the boat being 6 years old, I immediately notice a quieter ride and was most impressed by the 5-7% thrust improvement (3-5mph). We will be using it in our jet skis next

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by RMC: space

Excellent engine oil

Excellent outboard motor oil, engine runs smoother and quit with this oil. I would recommend this product for all outboard motor owners. Best product out there! I live in Hawaii and I never got any free shipping or any free products. Thanks!

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Bobby: space

Best for my boat!

I have been using this in my Yamaha 150 4 stroke for over 10 years. I recently replaced the balancer and had the opportunity to inspect the engine internally from the bottom end. I observed absolutely zero wear on visible internal engine parts and the engine was so clean inside it looked brand new!

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by West Coast Boater: space

Trusted product

Use it on both my Yamaha 2016 115 hp and 2017 9.9 high thrust motors.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Tomace: space

Runs in everything

Keep the motor cool and quiet

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Chris: space

Love this stuff

Just recently bought a chaparral SSI sport bowrider boat took it out twice and got 47 miles per hour. change the oil to amsoil 10w 30 for boats take it back to the lake and ran it hard and got a solid 50 miles per hour.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Reeling: space

Great product

I use Amsoil in my boat for the last three years. The engine seems more quiet and the oil level stays at the same level throughout the boating season.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Chris: space

So far so good

I bought a Seadoo GTR 215 supercharged unit and was looking for oil to complete an oil change. I've had great success with Amsoil in the past in sleds and atvs so I wanted to use in my Seadoo. I had read mixed reviews about using the Amsoil Synthetic marine oil in the supercharged skis due to supercharger clutch slip. But so far I've had no issues after approx 12 hours of riding.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Bob: space

25W-40

We use this product for a 60HP Mercury 4-stroke outboard motor. Love the product, and it is a great value also!

Item Reviewed: Formula 4 Stroke Marine Motor Oils

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Millerlite66: space

Works for me

I run this oil in a 1988 Glastron. I'm the second owner. I have used the 10w40 Marine oil for the 18 years I have owned this boat. It has a 7.4 liter GM big block in it . I have never had an engine problem that had to do with lubrication. Just sayin.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mitchell: space

Not sure.

Can't tell the difference.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Louie: space

Outboards

Oil I could trust running offshore

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mismo Titan: space

Simply the Best

We run our sea doos hard and this oil has never let us down. For supercharged skis there are no friction modifiers and it's JASO MA2 which is safe for our superchargers. I've been running amsoil in all my products for a while now and won't run anything else.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Jeff: space

Loyal customer

Good product, quick delivery, nice website, I'm a fan of Amsoil.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Reggie: space

Very impressive product

Developed for Outboards; oil is cleaner after use than regular oil

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Bobo0415: space

4-Stroke Suzuki Outboard

Better than Mobile 1. Increased top end, engine runs more smooth at idle. Don't waste your time buying oil from the outboard manufactures, over priced and over rated. Amsoil exceeds Suzuki requirements and will not void warranty. Bought a case, saved on the shipping.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by DonV: space

Only the best

This was my first oil change on my new outboard. I really never considered any other oil. I also used this same oil on the last 4-stroke outboard I had and it performed perfectly.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Showman: space

Great oil

I started using amsoil in my Yamaha because I did not have hour meter to keep track of hours thinking amsoils superior oil would give me some forgiveness if I went a little over recommend hours. I added hour meter, will still use amsoil under preferred customer plan.

Item Reviewed: Four Stroke Marine Motor Oils (WCF,WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by 4 to 1: space

Yes

Yam sport boat

Item Reviewed: SAE 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by 4to1: space

Yes

Yam sport boat

Item Reviewed: SAE 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by erictm: space

Great Product

Using it in my third engine with great results. Not a repair one on the first two. Keeps engine very clean.

Item Reviewed: SAE 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by matt: space

best of the best!!

having a $15k investment and protecting it starts with Amsoil. I use it in everything I own an have had ZERO problems.

Item Reviewed: SAE 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by tootall: space

Will buy this product again

Use in my 150HP and 9.9HP Suzuki Outboards

Item Reviewed: SAE 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Ronald: space

Best oil I've used in my four-strokes!!!!

I have been using this in my 4 strokes for 10 years- first in Honda 130's and now in Yamaha f250's. I have used Mobil 1, Honda and Yamaha oils and the amsoil is always cleaner at the end of the season and still has a goldish brown color.

Item Reviewed: SAE 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT)

Reviewed by James B: space

Honda BF115

Switched to 10W-30 Formula 4-Stroke marine oil in a Honda BF115 2.3L outboard motor and immediately noticed reduction in engine noise. It hums along much more quieter in all rev ranges, its just that much more smoother to operate this motor. The fuel economy is also better, able to go further with the same amount of fuel. All of it indicating one thing... reduction is internal friction! Will continue to use this product.

Item Reviewed: SAE 10W-30 Formula 4-Stroke® Marine Synthetic Motor Oil (WCT)
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