4-stroke oils certified for marine use

Author:
Publish date:

The bar finally has been set for 4-stroke marine oils. The national trade association for boatbuilders and engine manufacturers approved a new certification program, currently dubbed 4T, under which new-technology outboard and sterndrive oils will be tested to ensure they meet minimum specifications for use in the high-rpm, corrosive marine environment.


The bar finally has been set for 4-stroke marine oils.

The national trade association for boatbuilders and engine manufacturers approved a new certification program, currently dubbed 4T, under which new-technology outboard and sterndrive oils will be tested to ensure they meet minimum specifications for use in the high-rpm, corrosive marine environment.

The oils will carry a "4T" designation on their labels.

The 4-stroke marine oil certification program applies standards similar to the National Marine Manufacturers Association's successful TC-W3 benchmark for 2-stroke marine oils, says Geoff Kilburn, retail products manager for Mercury Marine.

There are differences between oils designed to run in automobile engines and 4-stroke outboards. For one thing, Passenger Car Motor Oil-certified products don't contain rust inhibitors and won't pass the 4T certification, according to Claude von Plato, national manager of Yamaha's parts and accessories division.

Because the Environmental Protection Agency is mandating longer catalytic converter warranties, the automotive industry is formulating automobile oils with less zinc dialkyl dithiophosphate, an anti-wear agent particularly effective in high-load areas, such as those experienced routinely in boating, von Plato says. Yamaha's 4-stroke Yamalube, for example, contains twice the ZDP of forthcoming SM category automotive oils, he notes. Furthermore, von Plato says, NMMA's oil certification committee was concerned about the lighter oils used for improved fuel economy in cars, which don't protect as well at higher loads.

The committee also added a corrosion test, an area not covered by the PCMO standard and important for marine oils, he says.

"There will be a significant difference between a 4T oil and anything you buy at Pep Boys," says von Plato. He says the program gives boat owners a way to judge what oil they should be using.

"We think it's great," says Mercury's Kilburn, "because sometimes the consumer is unaware and can be doing harm to their engine without even knowing."

In addition to highlighting differences between automotive and marine oils, 4T certification will tell boat owners that the product they choose contains all the necessary additives to perform under marine conditions.

"If you want to make oil cheap, remove the additives," says von Plato. He says it is possible for aftermarket companies to continue removing additives until their oils just pass the tests.

Von Plato and Kilburn both recommend sticking with your engine manufacturer's branded oil. Von Plato adds that the market for 4-stroke outboard oil isn't very large, and he doesn't expect much aftermarket activity in the segment.

Kilburn recommends other 4T-certified oil as a second choice. "I fully expect competitive companies to come out with [4T] qualified oils," he says.

The oil certification committee - which includes representatives from engine, oil and additive manufacturers - meets at least twice a year, von Plato says. He says an oil company representative presented the group with the worrisome trends in PCMO products a couple years ago.

Mercury offered its proprietary rust test, and Southwest Research Institute of San Antonio fine-tuned it, von Plato says. After much work, the committee ended up with an accurate, repeatable test, he says.

"It takes a long time to get that done," von Plato says.

Kilburn says Mercury started on its new formulation, which is ready to be tested, about 18 months ago.

The TC-W3 standard for 2-strokes has also been strengthened. Von Plato says an additional lubricity test has been added to discern problems seen with some 2-stroke oils on the market. He says all TC-W3 oils will have to be recertified.

"Any of the OEMs' 2-cycle lubes are fine; they're a fine product," says von Plato, who adds that the same goes for 4-stroke oils.

Certified oils will be listed on the NMMA Web site (www.nmma.org) as they are registered, says NMMA vice president of engineering standards Tom Marhevko.