Section 1051.25 - What requirements apply when installing certified engines in recreational vehicles?(a) If you manufacture recreational vehicles with engines certified under § 1051.20 , you must certify your vehicle with respect to the evaporative emission standards in § 1051.110 , but you need not certify the vehicle with respect to exhaust emissions under this part. The vehicle must nevertheless meet all emission standards with the engine installed. You must also label fuel tanks and fuel lines as specified in § 1051.135(d) .(b) You must follow the engine manufacturer's emission-related installation instructions, as described in § 1051.135 and 40 CFR 1068.105 . For example, you must use a fuel system that meets the permeation requirements of this part, consistent with the engine manufacturer's instructions.(c) If you obscure the engine label while installing the engine in the vehicle such that the label cannot be read during normal maintenance, you must place a duplicate label on the vehicle as described in 40 CFR 1068.105 . 67 FR 68347 , Nov. 8, 2002, as amended at 73 FR 59245 , Oct. 8, 2008