Remove the xducer and stick down in the water well past where anything could possibly block the SI beams...

If the issue disappears ...something on your boat is blocking the beam or the xducer is "way" out of level side to side...

If the issue is still present ...something is amiss either in the xducer or the control head...

The best test in this scenario is to cross test your head unit on another SI unit or another SI xducer on your head unit...

Rickie