There are different reasons why one side of the Si sonar would give a stronger return versus the other:
- The area you went over slopes from the right down to the left. Try running the same track but in the opposite direction.
- There is some type of partial blockage of the left Si sonar beam.
- The rotational angle of the transducer is off (it looks twisted clockwise or counterclockwise when viewed from behind). Note that the way the boat moves through the water and/or boat loading can affect this.
- There is something wrong with the Si transducer that is causing this.