Helix 7 Chirp SI GPS G2N interference problem

[bnewman046]

Ok, need some advice. I have one Helix 7 at console and one at bow. Ran dedicated 10 ga marine wire from crank battery to console fuse block. Fuse block powers Helix units only. Ran twisted 12 ga wires from fuse block to bow (ran through rod box - not running with trolling motor power wires). Console unit works great, no interference at any time. On bow unit, when I hit the switch on trolling motor I have interference on SI only. 2D and DI are great. Trolling motor is 9 year old MK Maxxum 80, Helix units were purchased new this year. Console unit utilizes the XNT 9 SI 180T compact side imaging transducer, bow unit has XTM 9 SI 180T trolling motor transducer.

Suggestions on where to start? Ferrite rings, ground wire from mtr head to neg, etc. I'm gonna call Humminbird on Monday but thought I'd try here also. (Btw, I never put the trolling motor on 100% and checked if interference was still there - too busy fishing!)

Thanks!

[Wayne P.]

If you have RFI on SI, you have it on DI also since they are exactly the same. DI is created by blending the two SI pulses.

You may have worn brushes, bent prop shaft, out of balance prop, or water intrusion as a start to figure out RFI.

Also check for damaged transducer cable.
Worn brushes on a 9 year old motor is highly likely.

[bnewman046]

Wayne - thanks for the quick reply! May start with replacing brushes and see where that leads. I know what you said is true, but DI was crystal clear. Just my luck, I've probably got a unicorn! Thanks again.