… I never set mine up in the auto mode. I manually set my depth range, sensitivity and everything else manually. One other thing I see most people doing is using fish ID. I never used this function. It is not dependable.
I do the same thing. I have a Lowrance M68C, and, based on my limited research, that model appears to have been released in 2003. I always go full manual, and it marks fish just fine even though it is older technology.. I will probably be upgrading soon though.