Humminbird Side Imaging Forums
Side Imaging Forums => 898c SI => Topic started by: Slinger on April 13, 2015, 03:57:05 PM
-
I have a fiberglass multi-species boat with shoot-thru-hull and HD SI transducers connected to an 898C SI with a Y cable. The main motor is a Yamaha F150 outboard. This setup worked great for a couple of years, but the factory installed shoot-thru-hull transducer stopped working last fall. I cut that one off the hull, sanded down to the fiberglass, and installed a new XP 9 20 T in the same place. Now I'm getting interference from my main gas motor, but only when it's in gear and at RPMs above idle. If I put the motor in neutral and throttle up, there is no interference. Also, if the boat is moving in gear at idle speed or just a little faster, there is no interference.
The interference shows up as blue and green pixels from the top of the screen to the bottom, which turn to orange and red as the boat accelerates. At that point, the sonar loses track of depth. See the attached image. The vertical bars of blue/green pixels occurred when I hit the throttle with the motor in gear.
For troubleshooting, I did the following:
- turned off and stowed the trolling motor
- disconnected the other sonar unit and accessories
- removed the Y cable, using only the XP 9 20 T
- removed the transducer cable from the wiring channel in the side of the boat and ran it across the deck and straight into the back of the 898
- removed the temperature probe from the transom and pulled it up to the deck away from any other wires
- swapped a 798 in place of the 898
- reset to factory defaults
- adjusted the noise filter
None of the above made any difference. Well, the noise filter may have reduced it somewhat, but not enough to be useful. Any ideas?
-
Is your prop all dinged up?
-
No, it's a stainless 3 blade prop, and there's only one tiny ding on the edge of one blade that was there before the original transducer failed. It's really small (maybe 1/4" long, 1mm deep), and it wasn't a problem with the original transducer. Other than that, the prop is pristine.
-
In case it matters, here are couple of images that show the installation of the transducer and the external transom area. In the photo of the transducers (Humminbird on the right), you can see the transom plug right between them.
-
I don’t know than Slinger. Very rarely a nicked/bent prop will cause this but if it was not doing it with the original transducer it should not be doing it with the new transducer. Call the Humminbird Customer Service folks.
-
OK, thanks for taking a look. I'll post a follow up if I get it figured out.
-
Thanks, that may end up helping someone else with the same problem.