89.113—Smoke emission standard.
(a)
Exhaust opacity from compression-ignition nonroad engines for which this subpart is applicable must not exceed:
(b)
Opacity levels are to be measured and calculated as set forth in 40 CFR part 86, subpart I. Notwithstanding the provisions of 40 CFR part 86, subpart I, two-cylinder nonroad engines may be tested using an exhaust muffler that is representative of exhaust mufflers used with the engines in use.