I need some help setting up my humminbird 561 sonar. When I turn the unit on the sonar shows nothing but grey. I have reduced the noise and the sensitivity and it dulls down the grey but thats it. Never shows fish or much structure. I really know nothing about sonars and would like help atleast with basic settings to get the sonar going.

It is a simple gray scale dual frequency 2D sonar unit. It should work perfectly with no adjustments IF it has the proper power, the transducer is installed correctly, and you are on the water with the transducer submerged.

Well everything is mounted correctly and the supply power is directly from the battery. Transducer is mounted on the trolling motor, and still not a good reading. I will try to take a picture of the screen next time I go out to give a better illustration.

Since you have it on the trolling motor, does the screen look the same when the motor is running and when it is not running?