Americans are again taking to the water in record numbers and are spending more on new powerboats, with retail dollar sales expected to be up 8 percent in 2013, signaling that the mix of boats being purchased includes higher priced models.

Latest figures show that over 37 percent of the population participated in recreational boating at least once in 2012 – the largest number since NMMA began counting in 1990.

Currently about thirteen and a half million motorized boats cruise the seas, lakes and rivers of North America – logging some 700 million hours on the water in 2011. These vessels generate a yearly demand for an estimated 14 million gallons of outboard engine oils, with about two thirds of that being for two-stroke engines.

Impact on Lubricants

The continued demand for two-stroke oils reflects the fact that, unlike the motorcycle market, the outboard engine population is transitioning very gradually from two-stroke, known as 2T, to four-stroke (4T) engines. This is partially owing to the durability of older carbureted 2T engines, and the continued use of 2T direct fuel injection for high horsepower applications. However, the 2T engine weight advantage is diminishing, as lighter 4T engines are being introduced.

With factory shipments now predominantly 4T engines, engine oils that can lubricate these engines will increasingly take market share away from the 2T lubricants. However, because 4T engines consume less oil than 2T engines, the overall outboard oil market volume is expected to decline.

The 2T and 4T engines that power outboards have very different lubrication requirements. In 2T engines, the oil is mixed with the fuel and lubricates the engine as it passes through. It is then burned along with the fuel, and exits via the exhaust system. But 4T engines are lubricated by oil that repeatedly is pumped from and returned to a sump, just as in a car or truck.

Despite the differences, two key objectives of original equipment manufacturers producing these engines are the same: reducing emissions to satisfy the environmental requirements of the United Sates, Canada, European Union and other markets; and extending the life of their engines to reduce warranty problems and increase customer satisfaction.

To meet these objectives OEMs have introduced advanced 2T and 4T outboard engine technologies, which place severe demands on engine lubricants.

In response, the NMMA maintains three trademarked categories in its lubricant quality certification program to help boaters choose an oil that will protect the engine throughout its life. It also maintains a registration program that lists certified oils according to their brands.

TC-W3 oils are certified for two-stroke marine engines.

FC-W products are certified for four-stroke marine engines.

FC-W Catalyst Compatible certification covers oils intended for use in 4T engines that have an exhaust aftertreatment catalyst.

The slow transition from 2T to 4T engines is clearly reflected in the NMMA lubricant certifications – where the registration list is dominated by TC-W3, two-stroke lubricants. More than 200 products hold the TC-W3 designation, nearly twice the number of those with FC-W and FC-W (CAT) combined.

Some of the work being carried out by NMMA, marine engine builders and additive companies such as Infineum USA L.P. is designed to address two key issues currently impacting outboard engine performance. First is the potential engine damage that may occur if passenger car motor oils are used to lubricate the engines of four-stroke marine engines. Second is the safety, environmental and technology concerns associated with the use of ethanol blends above 10 percent in recreational boat fuel tanks and engines.

PCMO Wont Do

In regards to issue one, passenger car lubricants cannot adequately protect 4T marine engines.

Water presents one of the largest concerns regarding the protection of marine engines because, whether it is salt or fresh, it can lead to the corrosion of engine parts. Passenger car engine oils are simply not designed to provide the level of corrosion protection these engines require.

But it is not only in their corrosion prevention capabilities that passenger car engine oil formulations fall short of the performance requirements demanded by outboard engines. Because 4T outboard engines run faster than car engines, spend long periods running at the extremes of speed, and can spend long periods out of use, they have very specific requirements for improved bearing durability, wear protection and shear stability (see table, this page).

However, formulating lubricants to deliver all these attributes to outboard engines is not straightforward. It is not simply about maximizing performance in all these areas. The lubricant formulator must strike a careful balance between the chemistries designed to provide antiwear and corrosion protection because the underlying components compete with each other for the surface of the engine parts.

In our view, this fact alone means it is highly unlikely that a PCMO can be formulated to successfully do the job.

Clearly the best advice for boaters who want to ensure they protect their engines is to look for the NMMA logo on the outboard engine oil they select, and/or use the OEM-approved oil. This is becoming increasingly important as the formulation of oils designed for use in passenger cars moves even further away from the ideal standard required to offer the protection that marine engines need.

Infineum is working with its customers, along with the NMMA, to help inform boaters so that they can make the right lubrication choices.

The Ethanol Threat

The second concern facing the recreational boating industry relates to the Renewable Fuel Standard, known as RFS-2, which requires the yearly U.S. fuel supply to contain 36 billion gallons of renewable fuel by 2022. To help meet these aims, the U.S. Environmental Protection Agency has introduced ethanol as an energy-saving initiative and an alternative to petroleum-based fuels.

In pursuit of this goal, EPA is proposing to change the automotive and light-duty truck certification fuel to E15 – 15 percent ethanol – in its Tier 3 Motor Vehicle Emission and Fuel Standards, up from the current E10 level used in many gasolines. This means E15 is expected to become the predominant fuel in the U.S. marketplace in the next 10 to 15 years.

A series of engine evaluations, conducted by Mercury Marine and Volvo Penta, under the direction of the Department of Energys National Renewable Energy Laboratory, concluded that E15 fuels not only severely damage marine engines, but also cause them to exceed EPA emission standards.

The potential for boat owners to accidently use fuel with a percentage of ethanol above 10 percent will increase significantly if E15 becomes the primary fuel in the marketplace. Current labeling prohibits the use of E15 in engines other than post-2001 passenger cars, and any retailer who chooses to sell the fuel must post such warning labels at the fuel pump.

While marinas will continue to carry gasoline for marine engines without ethanol, if E15 becomes the most available fuel in the automotive marketplace, misapplication seems inevitable. Boat owners who misfuel their vessels are unlikely to be covered by their manufacturers warranties.

The NMMA believes there are serious and well-documented human safety, environmental and technological concerns associated with the use of E15 in recreational boat fuel tanks and engines. This has prompted the organization to urge EPA and DOE to appeal to Congress and the President to freeze ethanol at 10 percent, while neutral party technical evaluation are conducted to assess alternatives that can be introduced at a higher concentrations, without the negative effects of ethanol.

These issues demonstrate how consumer education is becoming increasingly important in the powerboat engine industry, as well as in other engine industries where the lubricant and fuel requirements continue to diverge. Boaters simply cannot treat their outboard engine in the same way as their car engine.

Tom Marhevko is vice president of engineering standards at the National Marine Manufacturers Association, which represents the recreational boating industry and maintains oil standards that help assure the quality of outboard lubricants. Ed Post is North American specialties market manager at the global lubricants additive company Infineum USA L.P., based in Linden, N.J. For more information, visit www.nmma.org or e-mail e.post@infineum.com.