Converting Engine Data from NMEA 2000 to NMEA 0183
The only NMEA 0183 sentence that is currently used for engine data is RPM, so it is impossible for any manufacturer to create a conversion from NMEA 2000 to NMEA 0183 for all of your engine data.
In the latest version of NMEA 0183 released in June 2012, there are 148 sentences with between 550 & 570 data fields. In total contrast, in the latest version of NMEA 2000 released in February 2015, there are 163 PGN messages and 1569 data fields. Please refer to the NGW-1 Conversion List for details of all conversions that can be performed by the NGW-1 (and just as importantly those that cannot).