6.6.1 Air/Fuel Delivery - Four Stroke
Electronic fuel-injection systems: Flame arresters that meet USCG,
UL-1111 or SAE J-1928 Marine backfire flame arrester test standards
must be installed. If not equipped with an airflow sensor, the ducting
between the flame arrestor and throttle body may be modified or
aftermarket . If originally equipped with an airflow sensor, the ducting
may be modified or aftermarket between the flame arrestor and airflow
sensor. Modifications to the airflow downstream of the airflow sensor
are not allowed. No modifications to the turbocharger and supercharger
system, if applicable, are allowed.