My new (to me) boat came with an older fish finder, a Hummingbird LCR 400 ID. Was thinking of keeping it for now to learn from, I have never used one before as this is my first boat. Is this worthwhile, or is the unit to old to bother with?

If its to old, any suggestions on a decent newer unit. Not looking for anything special just a basic unit.

If it's in good working order , why get something else ?

Here is the manual for that unit. Turn off the fish ID for a more realistic view of the sonar returns. It marks just about all returns as fish including limbs, leaves, and bubbles.

http://www.humminbird.com/PDF/lcr400id.pdf

Read and study the manuel and please take the unit off automatic. Set it up the way you like and enjoy.