About Your EPA Certified Fuel Tank


By Brian Gordon, Last updated: 3/18/2022

Portable fuel tanks and fuel lines may look the same as they did decades ago, but changes mandated by the California Air Resources Board (CARB) and the United States Environmental Protection Agency (EPA) have, in some cases resulted in a poor customer experience. Our purpose here is twofold. First, we’d like to acquaint you with how today’s EPA compliant fuel lines and tanks differ from those of the past. Second and most importantly, this article will hopefully familiarize you with what you need to know to ensure a hassle-free experience with your EPA certified tank.

 

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EPA compliant primer bulb/fuel line assembly.

EPA Mandated Changes to Fuel Lines and Primer Bulbs

In 2009 fuel lines and primer bulbs were redesigned to include a barrier layer to prevent evaporation. This additional layer causes fuel line assemblies to be less pliable and more susceptible to permanent kinking. Purchasing the correct length fuel line is critical to allow for the larger bend radius required with CARB/EPA fuel lines versus the older “rubber” fuel line assemblies.

About the CARB/EPA Mandate

Since January 1 of 2011, CARB and the EPA have required that all portable fuel systems manufactured for use with outboard motors follow a near-zero-emissions policy. EPA certified tanks are required to hold a minimum of 5psi of internal pressure generated by ambient temperature changes or warming from the sun. Before the 2011 EPA mandates went into effect, fuel tanks generally included a fuel fill cap with a manually operated vent that allowed users to release vapor pressure in the tank to the atmosphere. Opening the vent and leaving it open also prevented a vacuum from developing in the tank that can stall an engine. When the vent was left in the open position, the tank became an “open system” that continuously released fuel vapors to the environment. To meet the new regulations, EPA certified tanks do not include this feature.

Meeting the Regulations: Two Approaches to EPA Compliance

Non-venting cap.

If you have a post-2011 Attwood or a 2011-2022 West Marine EPA certified tank of the same design, it will have a non-venting cap that looks like this.

As the old saying goes, “there’s more than one way to skin a cat”. We can see how this adage holds true in the two approaches manufacturers have taken to meet the EPA requirements. These approaches can be separated into venting and non-venting tank designs. The two approaches, while somewhat different, are both valid ways of meeting the goal, which is EPA compliance. We’ll go into the details in a moment, but what is important is that you understand what kind of tank you have and the procedures you need to follow to ensure a trouble-free experience when using your tank.

Non-Venting EPA Compliant Tanks

Examples of non-venting tanks include post-2011 EPA compliant Attwood portable fuel tanks and 2011-2022 West Marine fuel tanks that embrace the same design. These tanks are distinguished by a fill cap that allows air to enter the tank but that does not allow gasoline vapors to escape—unless you loosen or remove the cap. One drawback of these tanks is that ambient temperature changes or direct warming from the sun can cause them to swell. This is normal and should not be cause for alarm, but to limit the swelling we suggest you not overfill the tank (see “Final Recommendation—Never Overfill Your Tank!” below) and that you shield it from the sun. Excessive pressure within these tanks can also result in fuel getting forced through the fuel line which can flood or stall the engine. Another pressure related problem is messy (and hazardous) fuel spraying when the fuel lines are connected or disconnected from the tank. West Marine offers two retrofits to correct these problems.

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An FDV or Fuel Demand Valve.

To prevent engine flooding, owners of non-venting tanks should install a FDV (Fuel Demand Valve) between the primer bulb and the tank. FDV valves serve two functions. First, they prevent pressurized fuel from flowing through the fuel line and flooding the engine. Second, they allow fuel to flow at atmospheric pressure to the engine when a demand is placed by the engine on the downstream side of the valve. NOTE: The valve includes a manual override that enables fuel to flow in case the valve is blocked.

To prevent fuel from dangerously spraying when connecting or disconnecting the fuel line to the tank, we recommend that before connecting or removing the fuel line, that you first loosen the fuel fill cap which will relieve pressure from the tank. Since users often forget to do this, we strongly suggest use of an EPA compliant sprayless fuel line connector for the tank.

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Universal sprayless tank fuel line connector. The fitting on the left plumbs to the tank's fuel pickup. The fitting on the right plumbs to the fuel hose.

While you can purchase a sprayless connector and an FDV valve separately, the easy “once and done” solution is to purchase an EPA compliant West Marine Platinum Fuel Line Assembly which includes the FDV valve, primer bulb, fuel line, sprayless connector for the tank and a choice of engine fuel line connectors that fit to a wide variety of outboard motors.

As stated before, to minimize tank swelling, we also recommend that you shield the tank from the sun and that you store the tank in a cool place when it is not in use.

New West Marine and Moeller EPA Certified Portable Fuel Tanks

In 2022, West Marine and the marine fuel tank manufacturer Moeller partnered to offer a new type of EPA compliant tank. Like other EPA certified tanks, these tanks are required to hold up to 5psi of pressure caused by ambient temperature changes or heating from the sun. The most significant difference between these tanks and the non-venting tank described above is the multi-function tank fill cap. These caps can be clearly distinguished from others by the red button in the center. Understanding how the multi-function cap works and following the correct procedure when connecting or disconnecting fuel lines is your best guarantee of a hassle-free experience with this new line of West Marine and Moeller tanks!

Features and Benefits of New West Marine and Moeller EPA Certified Portable Fuel Tanks

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View of multi-function fill cap, fuel pickup and fuel gauge sight glass as seen on new (beginning in 2022) West Marine and Moeller portable fuel tanks.

  • Cap includes vacuum valve that allows air to enter the tank as the fuel level is drawn down by the engine.
  • Cap does not vent pressure out of the tank, unless the pressure exceeds 5psi, at which point a 5psi pressure relief “poppet” valve opens to reduce the pressure in the tank.
  • Cap includes a button that the user can manually press to completely vent pressure from the tank before fuel lines are connected or removed. This eliminates the need for sprayless fuel line connectors.
  • Cap includes a user operated valve that completely seals the tank prior to storage.
  • Cap does not vent pressure out of the tank, unless the pressure exceeds 5psi, at which point a 5psi pressure relief “poppet” valve opens to reduce the pressure in the tank.
  • Cap includes a button that the user can manually press to completely vent pressure from the tank before fuel lines are connected or removed. This eliminates the need for sprayless fuel line connectors.
  • Cap includes a user operated valve that completely seals the tank prior to storage.

Additional Features and Benefits of New West Marine and Moeller EPA Certified Tanks:

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Depressing the center of the red button releases pressure in the tank.

  • Heavier construction reduces swelling.
  • Half-gallon fuel “reserve” sump at the bottom of the tank.
  • Fuel pick-up connection rotates 360° for easy fuel line connection.
  • Glass fuel gauge sight window won’t discolor in the sun.
  • High profile fill cap, sits “proud” above the level of the fuel pick up connection. This protects the fuel pick up connection from damage in limited clearance situations.

When connecting or disconnecting the fuel line from your new West Marine or Moeller EPA certified tank, please follow the procedures listed below.

Connecting Fuel Line From Outboard—Order of Operation:
  1. Rotate the red button on top of the cap counter-clockwise to the open position. Remember this DOES NOT vent the tank. Remember, EPA tanks hold up to 5psi pressure.
  2. DEPRESS THE RED BUTTON AND HOLD DEPRESSED FOR SEVERAL SECONDS to release any pressure that may have built up in the tank.
  3. Connect fuel line to tank and pump primer bulb to prime engine for starting.
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When preparing to use the tank, rotate the red button counter-clockwise. Before storing your tank, rotate the red button clockwise to prevent air from entering.

Disconnecting Fuel Line Between Uses—Order of Operation:
  1. DEPRESS THE RED BUTTON AND KEEP DEPRESSED FOR SEVERAL SECONDS to release any pressure that may have built up in tank.
  2. Disconnect fuel line assembly from tank.
  3. Rotate red button on top of the cap clockwise to the to the closed position to prevent damp air from entering tank and potentially condensing.
  4. When the cap valve is in the closed position, the tank should be stored out of direct sunlight in a cool dry place.

Final Recommendation—Never Overfill Your Tank!

Regardless of the type of tank you have, you should never fill it beyond its rated capacity. The reason for this is that tanks are designed with some extra space at the top to accommodate gasoline expansion—and it is surprising how much gasoline can expand!

Now, for technically minded boaters, the expansion of gasoline is a function of its increase in temperature. The coefficient of expansion for gasoline is .069 percent per degree Fahrenheit of temperature increase. While that might not sound like much, what this means is that if you (for example) fill a six gallon tank with gasoline in the morning when the temperature is 60 degrees; by afternoon when the temperature reaches 90 degrees, the volume of gasoline (assuming you have not used any) will have expanded to slightly over 6.12 gallons. For those who doubt this, here is the calculation: (.069/100) x 30 [Temperature increase in degrees F.] x 6 = 6.12. So if you happen to have filled the tank to the brim, that extra .12 gallon will have to go somewhere. If the tank does not expand enough to accommodate the increase, the gas will find a way out, either by leaking out the flanges, leaking via the 5psi pressure relief valve (if your tank is so equipped) or in a worst case scenario, splitting the tank. So please, don’t overfill your tank!

Features and Benefits of New West Marine and Moeller Portable Fuel Tanks

 New West Marine (as of 2022) EPA Certified TankMoeller EPA Certified Tank
Wall ThicknessThick walls minimize swellingOEM quality construction reduces swelling
Fuel Line ConnectionRotates 360° for easy fuel line connectionRotates 360° for easy fuel line connection
Fuel Gauge Sight WindowGlass lens not affected by UVGlass lens not affected by UV
FDV ValveNone requiredNone required
Built-in Pressure Relief Valve?Yes, 5psi "poppet" valve built into capYes, 5psi "poppet" valve built into cap
Manual Pressure Relief Valve?YesYes
Fuel Reserve Sump.5gal. "limp home" capacity.5gal. "limp home" capacity
Ethanol Compatible?YesYes