Equipment Standards


183.534 - Fuel filters and strainers

If tested under Sec. 183.590, each fuel filter and strainer, as installed in the boat, must not leak more than five ounces of fuel in 2-1/2 minutes inclusive of leaks from the fuel pump and fuel line.

Fuel filters, strainers, and their connections must withstand a 2-1/2 minute fire test conducted as described in 183.590. The fire test may be performed on an engine for filters and strainers designed to be engine-mounted or may be performed in a fire chamber to qualify a filter or strainer to be mounted anywhere in the fuel system.

After the fire test, the filter or strainer is to be subjected to a 3-foot head of fuel to determine its rate of leakage. Acceptable leakage is up to 5 ounces of fuel in 2-1/2 minutes, but must include leakage from an associated fuel pump and fuel line. Internal leakage, destruction of straining or filtering elements, and impairment of function are acceptable.

FIGURE 19 - Leakage Test For Fuel Filters And Strainer


  • Each fuel filter, strainer and its connections will not leak more than 5 ounces of fuel in 2–1/2 minutes after the fire test in 183.590.


183.536 - Seals and gaskets in fuel filters and strainers

(b) Each gasket and each sealed joint in a fuel filter and strainer must not leak when subjected for 24 hours to a gasoline that has at least 50 percent aromatic content at the test pressure marked on the fuel tank label.

Fuel is made up of basic petroleum products in various quantities or concentrations. Depending on the amount of these components, fuel may have varying effects on the materials used for gaskets and seals. Fuels with high aromatic content have been found to damage fuel system components such as gaskets, seals, hoses and other usually non-metallic items.

To test gaskets and seals, it is required to subject samples to gasoline with at least a 50 percent aromatic content for a period of 24 hours. The described fuel is to be placed in the filter or strainer at a minimum head of 3-feet. After the 24-hour period, there shall be no leakage external to the tested unit.

FIGURE 20 - Seals and Gaskets Leakage Test


  • There is no leakage due to gasket or seal deterioration when tested to 183.536(b).



183.538 - Metallic fuel line materials

Each metallic fuel line connecting the fuel tank with the fuel inlet connection on the engine must:
(a) be made of seamless annealed copper, nickel copper, or copper nickel; and
(b) except for corrugated flexible fuel line, have a minimum wall thickness of 0.029 inches.

If metal is used for any portion of the fuel line (except for fittings) from the tank connection to the engine connection (usually at the fuel pump), the metallic fuel line portions must be seamless, annealed:

(1) Copper;
(2) Nickel copper (Monel); or
(3) Copper-nickel.

No other metals are permitted.

Also, the thickness of the tubing wall must be at least 0.029 inches unless the fuel line portion is a corrugated or accordion type of flexible fuel line. Tubing is available with thinner wall thicknesses, but they SHALL NOT be used.

Metal fuel lines used on the engine, i.e. the fuel line from the fuel pump to the carburetor, may be made of materials other than those listed. This line is usually supplied with the engine.


Are metallic fuel lines made of seamless annealed:

  • Copper;
  • Nickel copper; or
  • Copper-nickel?

Is the thickness of the fuel line tube wall at least 0.029 inches?


Previous  |  Next


Media and Marketing Materials

Members of the press, boating safety specialists and advocates, and the general public are invited to utilize any and all of the media and marketing materials in this section.


Photo Library

The U.S. Coast Guard has provided the Image Library as a resource tool for boating safety specialists, advocates and the general public.


Video Library

The U.S. Coast Guard has provided the Video Library as a resource tool for boating safety specialists, advocates and the general public.




   safe a float