Mercury Mariner 4 and 5HP 4-Stroke Outboards Service Shop Manual 1999, Page 98Get this manual
EMISSIONS
Dealer Responsibility:
When performing service on all 1998 and later outboards that carry certificationattention must be given to any adjustments that are made that affect emission levelsAdjustments must be kept within published factory specificationsReplacement or repair of any emission related component must be executed in manner that maintains emission levels within the prescribed ce rtification standardsDealers are not to modify the engine in any manner that would alter the horsepower or allow emission levels to exceed their predetermined factory specificationsExceptions include manufacturers prescribed changes, such as that for altitude adjustments
Owner Responsibility: