Fish finder noise from trolling motor

[moguy1973]

So I just recently installed a Minn Kota Maxxum on my boat and at the same time I installed a Garmin echoMap 54dv on it.  Today I took it out for the first time with that setup.  When I have the finder showing traditional 2D sonar it looks fine until I start the trolling motor.  I then get real thin vertical lines that show up coming off the bottom of the screen.  It's almost like the transducer is picking up the blades on the trolling motor because the lines are equidistant from each other.  The problem is MKs have the skeg on the front of the motor and the Garmin transducer for that unit is HUGE and takes up a majority of the bottom of the rest of the head of the motor and I have it as forward towards the skeg as possible.  Any suggestions?

Picture of the transducer on the trolling motor. 

[Wayne P.]

When you get those vertical lines with the motor operating, that is RFI. Something you have to deal with when putting a transducer on a trolling motor if your motor is broadcasting on the same frequency/s as the sonar unit.

There are numerous possible remedies for that issue with installation being the first thing to check.

Transducer cable not attached to the cable from the foot pedal to the motor top is one of the most common installation errors.

Do a web search for trolling motor RFI to see what to do and what not to do with an installation.

[moguy1973]

I found a video where a guy routed the xducer wire along the Maxxum mount instead of down the TM control wiring.  I'll try that to see if it helps.