What is the model # of the Raymarine AIS.
Generally, the AIS transceiver can send (output) low speed (4800 baud) data but, the caveat is that the NMEA0183 data sentences should include the following, for your M803 to display GPS lat/long, and time:
GGA, GLL, GNS, RMC, VTG.
From memory, GGA is the sentence that will provide position and time.
Having said that, unless I know the AIS model you are using, I cannot provide you with a solution for the correct wiring
output from your AIS to the M803.