# Electrical noise from main motor



## Steamboat (Oct 12, 2009)

I have a Humminbird 597 HD DI that seems to be affected by electrical noise from the main engine. At slow speeds, the image is perfect but once I push the throttle down past a certain point, I get interference, I back down and instanly it gets clear again....its like turning a switch on and off. I did notice the the spark plug boot was not snapped snug on a spark plug today....would that cause it? I have the unit connected directly to the cranking battery....inline fuse nearer to the unit rather than the battery (which I heard can be bad)...Do you guys route the transduce cable or any of the other cables away from any other wiring. Thanks in advance for your thoughts.


----------



## Bad Bub (Jan 17, 2006)

Actually your problem may have more to do with air bubbles coming from under the boat at high speed. You may have to try moving the transducer around on the transom.

Outdoor Hub mobile, the outdoor information engine


----------



## Steamboat (Oct 12, 2009)

I wondered about that. I have a Lund that has a board mounted on the transom for transducers etc...I tried to keep the puck as far away from the motor as possible. The bottom of the puck in just a hair below the bottom of the boat. Maybe move it deeper? Thanks for the suggestion.


----------



## rockytop (Mar 19, 2008)

put the motor in neutral and increase the RPM. if the screen looks ok then its cavitation and you will have to move the transducer. but if the noise is there in neutral you might need resistor spark plugs, or a alternator filter and routing the power cables away from the engine wiring.


----------



## spinningwheel (Aug 6, 2007)

Steamboat, I have the 596c HD DI with the same problem. It works like a charm until I get on plane or in rough water and then the screen fills with vertical lines and becomes unreadable. I contacted HBirdDeborahCHC, who is a member here and also a H'Bird rep. for help and worked with her throughout this season. We eliminated the most probable causes such as running the wires too close to the other power lines, changing from the house battery to the starter battery etc., and then decided that it is the way the 'ducer is mounted to the boat. I have a 1989 23' Imperial cuddy and it has a pretty strange chine at the transom, so I couldn't get the 'ducer mounting the required 15" from the prop; I'm only about a foot from it. The last suggestion was to mount a shoot through 'ducer to the inside hull of the boat, which I will try next season as I'm already out of the water for winterizing and storage this year. 
Hope this helps.


----------



## Steamboat (Oct 12, 2009)

Thanks for the suggestions. Ill try moving the transducer around.

Outdoor Hub mobile, the outdoor information engine


----------



## buzzjet (Nov 7, 2011)

You need to check not only the transducer routing but the power routing as well. You really would like to have both routed / separated from the boat's wiring if possible. Also, it is normally a good idea to run independent power / ground wiring from the unit to the battery directly. If you have the unit powered from the boat's power, some of that interference could be coming from there. The boat wiring could be picking up that interference and transfering it to each device that is connected to it. This is normally the first steps to take to try to eliminate the interference you are getting.


----------



## tomb (Oct 9, 2004)

What frequency is the unit set for 200 or 60


----------



## Steamboat (Oct 12, 2009)

I moved the transducer around and that helped a bit but still not a great image and still seems "overwhelmed" at times. Im pretty sure its turbulence though. I have better luck with the narrow cone (not sure what frequency that is) rather than the wide cone. Do inside the hull transducers work ok with an aluminum hull? Thanks for your help everyone.

Outdoor Hub mobile, the outdoor information engine


----------

