Have a Humminbird 688 on my bow trolling motor. Unit has worked great, but a few days ago when I would mash the trolling motor button on the foot pedal, lines would show up on the graph. When I let off the foot pedal the lines stop. Just wonder why all the sudden this is showing up. I did put a piece of rubber between the transducer and the trolling motor, but didn't change anything. Any suggestions? Thanks.
Posted By: Wayne P.
Re: Interference on graph. - 11/30/17 11:54 AM
Getting RFI when you did not have it previously can be caused by several things:
Worn motor brushes
Bent prop shaft
Damaged/out of balance prop
Damaged motor shaft seal/water intrusion
Damaged transducer cable
Posted By: Tjhook
Re: Interference on graph. - 11/30/17 05:30 PM
Could be trolling motor yes. But l check your big motor. There's these little rectangular blocks that are anoids. If there is white corrosion all, over then sand it and clean it and see if it continues. If it helps then you have something else beside the TM issue.