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Typical auto oils don’t contain corrosion inhibitors marine engines need to guard against the uniquely harsh environment that marine engines operate in. In the example to the right, samples have been cut from the actual cylinder walls of marine engines that were run with automotive, typical marine and Quicksilver oil. As you can see, the Quicksilver oil offers the best protection against corrosion.

Load and Heat

Imagine driving your car at 80 mph while pulling a boat while driving up a 30 degree incline—all the time. That’s the kind of stress your marine engine is under. Automotive oil is simply not designed to withstand the marine environment.

Air Temperature

Automotive engine oils are designed to operate in wider outside air temperature ranges than marine oils. In order to operate as efficiently as possible over these large temperature ranges, automotive oils use viscosity Improvers (VI). This is a bit of an oversimplification, but VI are added so that oil can be as thin as possible while still meeting desired performance characteristics over wide temperature ranges. But VI aren’t necessary in marine engines because it is more beneficial for marine oil to as thick as possible and still operate efficiently.

Simple enough, right? Well, it gets a bit more complicated since a number of marine engine oils on the market today may not be true marine engine oils. There is nothing that prevents a company from taking automotive engine oil and labeling it as marine engine oil.

If you check your sterndrive or inboard owner’s manual, chances are your manufacturer recommends the use of an FCW® certified marine engine oil. FCW certified oil has been approved by the NMMA (National Marine Manufacturers Association) for use in four-stroke marine engines.

To help boaters protect their investment and to ensure a positive boating experience, the NMMA and leaders in the marine industry have developed a four-stroke marine oil certification called FCW. Products that have the FCW have met minimum testing and quality standards. There are roughly a dozen tests conducted to review viscosity, corrosion, filter plugging, foaming and aeration. In addition, the oil must successfully pass a 100-hour general performance engine test. Engine manufacturers such as Mercury Marine perform additional tests to ensure that our oils exceed these minimum standards. To learn about the NMMA go to

All Quicksilver four-stroke engine oils are FCW certified by the NMMA.


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Quicksilver 4 Stroke Outboard Oil Filter

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Highest quality Quicksilver outboard filters and coupled with Quicksilver 4 Stroke Outboard Oil work together to provide the ultimate protection and longevity for your engine.

From: £12.95

Quicksilver's all new 4Stroke oil technology outperforms automotive oils in marine applications because of its specialised additive package designed for marine engines.

From: £11.99

Inboard & Sterndrive Engine Oil 4Ltr - A 25W-40 oil formulated for 4 cycle marine inboard and sterndrive engines.

From: £13.50

Quicksilver 4-Stroke Oil is formulated for 4-stroke outboards operating at 5000-6000RPM at wide open throttle


Quicksilver Heavy Duty Diesel Engine Oil SAE 15W-40. Multigrade SAE 15W-40 diesel engine oil, formulated to meet heavy duty requirements and to combat sludge and varnish formation.


Quicksilver High Performance Extreme Grease is supplied in a handy squeeze tube to keep on board your boat

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Quicksilver High Performance Gear Lube

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Quicksilver High Performance Gear Lube

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From: £10.50

Quicksilver High Performance Gear Lube features improved emulsifiers to help protect gears should water enter the gear housing and tackifiers to improve oil film adhesion to gears and internal components

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Quicksilver Merc Cruiser Oil Filter

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Quicksilver Merc Cruiser Oil Filter 35-866340Q03. Replaces: 35-802885Q / 35-866340Q


Quicksilver MerCruiser Oil Filter V-6 (Without Remote Oil Filter) 35-883702Q ​​​​​​​. Oil Filter to fit Mercruiser 4.3L V-6 engines, without remote oil filter. 


Quicksilver Optimax / DFI Oil 4Ltr - Two stroke oil, formulated to cope with higher operating temperatures and reduced oiling rates of Direct Fuel Injection outboards.


Quicksilver Power Trim & Steering Fluid is recommended for use in power trim and steering systems where ATF (automatic transmission Fluid) is recommended


Quicksilver Power Tune is an aerosol spray used for cleaning the inside of petrol engines


Quicksilver 2 stroke TC-W3 outboard engine oil specifically formulated with a marine additive package to meet the needs of low to mid horsepower outboard engines, under general marine operating conditions

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Quicksilver Premium Gear Lube - 1 Litre

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Quicksilver Gear Lube is a premium blend gear oil formulated especially for all outboards

From: £13.99

Quicksilver Premium Plus 2 stroke engine oil is specifically formulated with a higher concentration marine additive package to meet the needs of high horsepower outboard engines including direct fuel-injected engines in extreme marine operating conditions


Quicksilver 2 Stroke PWC Oil 946mlFormulated specifically for unique conditions found in marine environments, with full synthetic formula for maximum engine protection in all brands of 2-cycle PWCs and Sport Boats


Quicksilver Quickcare is a fuel treatment that can be used at every fill-up


Quicksilver Quickleen Engine & Fuel System Cleaner is suitable for use in all 2 and 4 stroke carbureted and fuel-injected petrol engines including inboards, outboards, jet skis, cars, motorcycles, lawn mowers, chain saws, strimmers etc


Quicksilver Quickstor is a fuel stabiliser that will prevent fuel break down and oxidisation for up to one year


Quicksilver Storage Seal Fogging Oil is a fogging spray that protects internal components from corrosion during storage