New gas tanks worry boaters

Mercury helps create valve to fix venting on outboard engines

Outboard-engine fuel tanks, that sometimes swell up like a balloon on hot days, have become worrisome for two of the nation’s largest boating organizations.

The newer-style portable tanks, that don’t have a traditional vent, are meant to prevent smog-causing gas fumes from escaping into the atmosphere. But in some cases they’ve put boaters in a bad situation, according to BoatUS, an Alexandria, Va., organization that advocates for recreational boaters and has more than 500,000 members.

“Our members are telling us that the new tanks aren’t all they are cracked up to be,” said Mike Vatalaro, executive editor of BoatUS Magazine.

Without a vent, typically a small screw-type fixture on the tank’s cap or top, a portable gas container can swell up in the hot sun, forcing fuel into the outboard engine where it can spew inside the cowling and dribble into places it shouldn’t be.

“Where the traditional tanks simply vent to the atmosphere, the new tanks won’t vent until the internal pressure reaches 5 pounds per square inch. In the meantime, fuel could be forced up the fuel line into the outboard engine, many of which have no means to hold it back,” Vatalaro said.

It’s a fire hazard, in addition to polluting the environment, said Charles Fort, BoatUS director of consumer affairs.

“If this happened in an enclosed space . . . it could be catastrophic,” Fort said, although he wasn’t aware of fires resulting from the problem.

Many boaters have seen swelling of their new portable fuel tanks, which they hadn’t experienced with older fuel containers, according to the National Marine Manufacturers Association, a Chicagobased trade group.

The new tanks, introduced in

2012 as the result of an Environmental Protection Agency rule change, were tested to remain sealed and safe even when swelling is visible. But if the pressurized fuel sprays out through the engine, or from a fuel line when it’s connected or disconnected, it creates a dangerous situation.

Addressing the problem, Fond du Lac-based Mercury Marine Inc. partnered with Attwood Corp., in Lowell, Mich., to develop a fuel-line valve that prevents gas from reaching an outboard engine when the fuel isn’t needed.

Mercury also developed a fuel-tank cap that, under a certain pressure, will vent gas fumes to lower the pressure to a safe level. But it won’t allow fuel to leak out of the tank when it’s jostled on a boat trailer.

Now, all of Mercury’s outboard engines that use portable fuel tanks come with the technology that’s EPA approved.

“Any time that you have fuel venting, there’s always a safety issue . . . you just don’t want to have gasoline spilling into your boat, or back by the engine,” said John Neville, Mercury’s director of global service parts division.

The issue has surfaced this year as many people have portable gas tanks without the fuel-demand valve. BoatUS recommends installing the $25 valve on tanks that need it.

“Without a vent, there’s no way to release the pressure that builds up in the tank when it gets heated by the sun. The result — entirely predictable to boaters, but apparently unseen by regulators — is gas pouring out of the outboard and into the water, driveway or backyard. And before you ask, leaving the tank disconnected just results in the same gush of gas once you do hook it up,” Vatalaro said on the BoatUS website.

The EPA says the change to the newer-style portable fuel containers has helped reduce harmful air pollutants.

“Nonroad engines contribute significantly to air pollution. In the Clean Air Act, Congress requires us to set emission standards that address the problem,” the agency says on its website.

You could open the fuel cap and relieve the pressure, but that defeats what the EPA was trying to accomplish with its zero-emissions plan, and it’s not always practical, said Charles Plueddeman, a freelance marine industry writer from Oshkosh.

If you don’t want to install one of the valves yourself, go to a marine dealer and get a fuel tank that already has it, Plueddeman said.