Problem with hummingbird helix 7 chirp g3

[Doug]

Hi I previously purchased a new hummingbird helix 7 chirp g3 . I have been on the lake with it twice and it's not marking any fish what so ever. Just wondering if anyone could help steer me in the right direction. Any info would be very appreciative thanks!

[Goosechaser]

Are you using a shoot through (the hull) transducer or a transom mounted?

[Doug]

Transom mount and it's mounted all the way to the starboard side all by itself , Even with the bottom of boat .

[Bankangler]

Here is my Helix 7 on the bottom On 200 kHz and 859 at 83 kHz on the top Both have skimmer transducers and I have the transducers mounted so the middle of the transducer is flush with the bottom of the boat and not transducers are tilted slightly down in the back. I can mark fish at 25 mph on both units.