Summary of Previous Emission Standards

(a) The following standards, which EPA originally adopted under 40 CFR part 91, apply to outboard and personal watercraft engines produced from model year 2006 through 2009: (1) For engines at or below 4.3 kW, the HC+NO X standard is 81.00 g/kW-hr. (2) For engines above 4.3 kW, the following HC+NO X standard applies: HC+NO X standard = (151 + 557/P0.9) ⋅ 0.250 + 6.00 Where: STD = The HC+NO X emission standard, in g/kW-hr. P = The average power of an engine family, in kW. (b) Table 1 of this appendix describes the phase-in standards for outboard and personal watercraft engines for model years 1998 through 2005. For engines with maximum engine power above 4.3 kW, the standard is expressed by the following formula, in g/kW-hr, with constants for each year identified in Table 1 of this appendix: Table 1 of Appendix I—HC+NO X Phase-In Standards for Outboard and Personal Watercraft Engines Model year Maximum engine power <4.3 kW Maximum engine power >4.3 kW A B 1998 278.00 0.917 2.44 1999 253.00 0.833 2.89 2000 228.00 0.750 3.33 2001 204.00 0.667 3.78 2002 179.00 0.583 4.22 2003 155.00 0.500 4.67 2004 130.00 0.417 5.11 2005 105.00 0.333 5.56 [86 FR 34514, June 29, 2021]