Gasoline engines installed in a vessel after April 25, 1940, except outboard motors, must be equipped with an acceptable means of backfire flame control. The device must be suitably attached to the air intake with a flame tight connection and is required to be Coast Guard approved or comply with SAE J-1928 or UL 1111 standards and marked accordingly.
It should be attached to the carburetor or carburetors a backfire flame arrestor that is approved for marine use and suitably secured to the air intake with flame tight connections, or any attachment to the carburetor or the engine air induction system by means of which flames caused by engine backfire will be dispersed to the atmosphere outside the watercraft in such a manner that the flames will not endanger the watercraft, persons on board or nearby watercraft and structures. All attachments shall be of a metallic construction with flame tight connections and firmly secured to withstand vibration, shock and engine backfire.
