New Jersey Statutes Title 12. Commerce and Navigation 12 § 7-23.2

Every power vessel used on the waters of this State shall at all times be equipped with a muffler or muffler system in good working order and in constant operation.  A person shall not use a muffler or muffler system cutout, bypass or similar method or device designed to prevent or diminish the operational capacity of a muffler or muffler system installed on a power vessel used on the waters of this State.  Decibel levels exceeding the limits established pursuant to rules and regulations as measured by a noise meter operated by a trained Marine Police officer or municipal law enforcement officer shall be evidence of a violation of P.L. 1987, c. 269 (C.12:7-23.2 et seq.).  For the purposes of P.L. 1987, c. 269 (C.12:7-23.2 et seq.), muffler means a sound dissipative device or system which abates the sound of gases which are emitted from an internal combustion engine and which prevents excessive or unusual noise.