Depth finder flashing

[Im Lon 2]

My depth finder (3800 Lowarnce, factory installed) flashes, when traveling 20+ MPH, and when the water depth is over 25'. If I slow down it reads fine, and if the depth gets below 25' even at 20+ MPH it "seems" to work just fine.

I have a thru hull transducer and is located behind the engine. I have checked to make sure it was secure and there is no movement at all. Under side of the boat seems to smooth.

Any other ideas I should be looking at, or for?

 

[Silvertip]

If the transducer is installed in-line with anything on the bottom of the boat that can cause turbulence (air bubbles) that will cause the issue you are having. Since it is behind the engine, that also places it close to the outdrive so turbulence in that area can cause the problem as well. Dirty hull is another cause.