Owners with outboard powered boats have lived with portable fuel tanks for years, but recent well-intentioned efforts to stop smog-causing gas fumes from escaping by eliminating the familiar two-way vent is causing new concerns. Without a vent – typically a small screw type fixture on the tank’s cap or top – a portable tank can swell up like a balloon in the hot sun with the internal pressure forcing gas into the outboard where it can spew inside the cowling, eventually dribbling out.
According to BoatUS, it’s a wise move to install an inexpensive fuel-demand valve in the fuel line that will prevent any gas from reaching the motor unless the motor calls for it, and BoatUS has a video and easy to follow instructions to show you how.
“Our members are telling us that the new tanks aren’t all they are cracked up to be,” BoatUS Magazine executive editor Mike Vatalaro said. “These new EPA compliant portable tanks and jerry jugs have special fittings that greatly reduce evaporative emissions from gasoline. But where traditional tanks simply vent to the atmosphere, the new tanks won’t vent until the internal pressure reaches five pounds per square inch. In the meantime, fuel could be forced up the fuel line into the outboard, many of which have no means to hold it back.”