1986+ Mercury 6/8/9.9/10/15HP 2-stroke Factory Service Manual, Page 146Get this manual
EMISSIONS
Dealer Responsibility:
When performing service on all 1998 and later outboards that carry certification, attention 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 certification 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