Keeping in mind that the that the B148-12 is a 50/200kHz and 455/800kHz Lowrance Transducer. You should be able to use the 50/200kHz side with the GP1971F only. The existing transducer connector will not work, so you'll have to remove it and then splice in an Airmar 10-Pin Connector.
Please ensure to contact AIRMAR for any wiring diagrams.
-Deep Blue
Just to give you guys an update because no one got back to me.
I made a quick connect plug for testing purposes to go from simrad to furuno. It worked very well i was able to go from one machine to the other without any unwiring of the transducer. the b148-12 works fine at 50\200, Temperature also reading good. the 148-12 is set to b60 on furuno tzt3 .If you guys have any detailed questions PM me.