Faulty sonar readings

I installed a lawrance elite 4 chirp on my Revo 13 a few weeks ago, and I'm having issues with the sonar. It will work perfectly for a few hours, then it gets a blurred out screen, and starts blinking random depths. Sometimes it fixes itself after an hour or 2, other times it stays messed up. I've tried turning it off and back on, but this doesn't help. Has anyone else had this problem?

I have had this problem too with my Elite 4x, sometimes it will read >5ft when I'm obviously in several hundred feet of water or just no depth reading at all (but still reads water temp and SOG). I've adjusted sensitivity setting with temporary success but the issue came back. I recently readjusted the angle of my skimmer transducer that it was pointing ever slight downward rather than perfectly parallel with surface of the water. Since doing that (two long trips) I haven't had the issue but we will see.

Thanks Ak! I'll have to see if  my transducer is level.

I recently readjusted the angle of my skimmer transducer that it was pointing ever slight downward rather than perfectly parallel with surface of the water. Since doing that (two long trips) I haven't had the issue but we will see.

Interesting.  You could test the theory that your problems are being caused by the angle of the transducer with respect to the surface of the water by going out on the water in calm conditions, turning on your fish finder, and then first sliding way to the back of your Revolution, kayak, and then way to the front of your Revolution.  This would considerably change the trim of the kayak, and thus the angle of the transducer with respect to the surface of the water.  If changing the trim of your kayak affects the performance of your fish finder, that would tell you something. If changing the trim of your kayak doesn't affect the performance of your fish finder, that would also tell you something.

I suspect that you will find that changing the angle of the transducer with respect to the surface of the water won't have any effect on the problem.  If it did, as the nose of your kayak pitches up and down as you go over waves and swells, the problem would appear and disappear rhythmically as you went over the waves.  And you haven't mentioned that as a symptom.

On a couple of my Humminbird fish finders, after I had used the fish finder for a year or so, in the middle of a trip the fish finder would suddenly stop reading the bottom, or would produce other incorrect sonar readings.  I was able to fix the problems by brushing off the pins and sockets in the plugs as well as I could, and then globbing dielectric grease on them.  Give that a try, although it would surprise me if you were developing connection problems after using the fish finder for only a couple of days.

If your transducer is in the transducer pocket in the bottom of your Revolution, reach your finger into the pocket to see if any sand or mud has accumulated on top of the cover plate, and slide a piece of paper between the bottom of the transducer and the top of the cover plate to see if any mud or sand had built up in that narrow slot.  If it has, hose the debris out of the pocket and try your fish finder again.  If you pick up a bunch of sand or mud in the pocket while launching, you can get most of it out by standing in a couple of feet of water, reaching under your kayak, and swishing water into the pocket with your hand.  But the best way to get sand out of the pocket is by propping the kayak nose-up on something, and squirting water into the pocket with a hose.

If your transducer is in a transducer pocket, you could also experiment with changing the spacing between the bottom of the transducer and the top of the cover plate.  If one end or corner of the transducer is touching the plate, that might affect the performance of the transducer.

regarding the loss of depth reading, this happens now and then with all 3 of my Lowrance units (HDS8, Elite-7x, Elite-4chirp), my standard fix is to switch from auto range to a fixed depth so that I can see the bottom.  this confirms that the sonar is getting a good signal from the bottom which tells me that the software is just temporarily confused about the location of the bottom.    Once the numeric depth display comes back, switch back to auto range, all good, usually doesn't happen again...

That gives me a few things to try out. Thanks again! I'll test it out this weekend.

Used to happen to my lowrance made "eagle cuda" FF.  Typical for their lower end stuff.

Used to happen to my lowrance made "eagle cuda" FF.  Typical for their lower end stuff.

It's really irritating when your fish finder poops out when you're on the water, particularly if your fishing style relies heavily on use of a fish finder.  You made your fishing plans, you loaded up all your fishing gear, you drove to where you wanted to fish, you loaded and launched your kayak, you got out on the water and started fishing, and then PFFFT! No fish finder.  It's an experience you remember the next time you're in the market for a fish finder.

I found that most of the faulty readings from my sonars are due to wiring issues. The top of the list is corroded wiring near the connections for me. My typical routine is to trim the wire and reattach and if I have some dielectric grease I might use that on the connections. However if you have a faulty transducer install then it could be an issue. Good luck

In my experience all FF's do this at some time or another. Sometimes it's just what's in the water. Some problems outside of this might be something getting on the transducer itself. It could be mud, sand, air bubbles etc that are on there. Depending how your transducer is installed I'd look there for issues. I had the foam puck and water method going for many years and found that if I kept major debris out and wiped the bottom of the trans (to keep air bubbles off) before installing it was more reliable. When I used to rid e a Hobie with "Lowrance ready" I had some stuff get in there a few times and some interference with air bubbles.

Just my 2 cents, I have a Raymarine Dragonfly and on occasion it does the same thing. I have found it is usually a piece of debris like a bit of grass or kelp that drifted under my transducer. It's one of those Lowrance ready Hobies. I think it may get stuck or something for a minute. Then it returns to normal. It's strange but it doesn't happen often.

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My Dragonfly will at times get "lost."  For example, I turned it on while on shore at Potholes, taking some time to re-rig the kayak for two.  When I left shore the Dragonfly showed 1300 feet! 

Power off.  Power on.  All was well.

I have two Elite 4's and they both have problems.  One is less than a year old and it now almost always shows a completely white screen, but it shows the numerical depth, water temp and speed just fine.  The newer chirp version does something similar, but the screen is orange, like the sensitivity is too high.  After a while the chirp one will go back to normal.  Called Lowrance and they're having me send both units in to look at them.