After a quick re read, and I may have missed it, I don’t see where a call was made to either Garmin or Minnkota customer service and a chat with a tech CSR. DID that call(s) ever happen? I have a Humminbird Solix so I’ve only ever talked with Humminbird CSR’s and have found them very helpful.
Was your trolling motor and MFD purchased new?
Who installed these two systems? I’d go back over the installation instructions to make sure everything has been installed correctly.
Since you’ve added a plethora of those RFI beads with no resolution I’d say that is not going to be the answer to your problem.
The fact that when you increase the prop speed and the interference goes away is possibly pointing to your issue. To be clear there is no interference from prop speed 3 all the way up to and including prop speed 10? Could be an issue with the brushes on the armature of the motor. Which trolling motor is it exactly? If it’s a Quest series then there are no brushes but there is a brushless drive system in that motor that emulates AC voltage in a way that could be generating some interference at the lower prop speed.
There is supposed to be shielding on the transducer wire yes? If so is the shielding wire supposed to be grounded? Perhaps either the transducer cable has an issue or the Garmin unit or there is an issue with the trolling motor itself that needs the manufacturer’s attention.
Have those coils been like that the whole time? I’d uncoil those cables next to the mfd and also get them away from the stereo head unit. Coil the cables up some where else and away from each other.
Again, go over the installation instructions thoroughly to make sure there isn’t something simple and call Minnkota customer support, be sure and have the serial number of the troller handy as the CSR tech will want that as well as model information, same thing with the Garmin unit I’d imagine they will want the same information when you call their customer support.
Any chance you’ve got dimmed LED’s going on?
The majority of my boating trips involve running out before sunrise or coming back after sunset. I have two boats, and I got tired of trying to remember the layout of the switches at the helm of each of my boats. On my 255 FSH, the switch labels were impossible to read at night without turning on a light. The standard Map Light, even in red mode, was too bright and caused a dangerous reflection on the windscreen. Therefore, I decided to swap out all of the FSH's switches with backlit dual-lamp switches that I purchased from
New Wire Marine. Now, when I flip on the Nav lights, all of...
Also of interest
Question for you guys. So I have 3 lifepo4 batteries on order for a trolling motor installation. I naturally assumed that I would run a ground wire from the negative of the 36v bank to the negative of the house and start batteries, therefore holding the ground at the same electrical potential throughout the boat. When reading the installation manual of the motorguide xi5 manual, it says to only connect a common ground to a 12v trolling motor system and not on a 24 or 36 volt bank. Does anyone know the reason behind this? The only thing that I could think of is if the grounds are not...
Talked to my marine mechanic about your problem just now and he suggested the following….
Also, make sure the trolling motor power leads are NOT tied to or are in close proximity to the navigation lights wire runs. If so any radiation or noise could be induced into the house bank ground.
If the gps puck and or its wiring for the mfd is anywhere near the the trolling motor power leads this could also be a source of rfi.
Another possible fix would be to wrap the trolling motor power leads with a #14 green (green for ground) wire for the entirety of the length of its run with a relatively tight coil and attach the end closest to the 24V battery to the ground. This will act as an extra shield to capture any radiation coming from the power leads.
