This has been an ongoing problem for sometime now. I am at a wits end. I have called Hummingbird, talked with All Star Electronics and Rockwall Marine. Is anyone else having problems with their trolling motor, Fortrex 101 about 2 years old, and their front mount graph? First started with blue streaks at deeper depths, now it is bouncing depth ranges. I have already put a choke on and also insulated the transducer from the motor. All Star says now the only option left is to rebuild the trolling motor and run a ground wire from the trolling motor to the batteries. Is this a problem for anyone else?

Yes

Foretrex 80# Hummingbird 957. Check the fuse inside the top of trolling motor head. When you get yours figured out send me a PM on what you did. I just have not took the time to mess with it.

Make sure TM operating battery is diffrent than FF operating battery.
Just a thought.

Every time I hit the trolling motor button my Lowrance unit puts a line on the screen. Asked this same question and got 20 different rather complicated suggestions. Called Lowrance and they had no guidance. I just kept fishing.

Weird. I have no problems with my trolling motor/puck transducer and I'm running a bird 788ci up front. Not interference of any kind

Have you tried swapping out graphs to make sure the graph is not the problem?

Go look for post by Doug Vahenberg in the general equipment discussions. He has lots of information posted about how to correct these issues. I installed my graphs per all of his recommendations and have not had any interference issues to date.

My 858 h-bird does the same thing. But off and on sometimes it works flawlessly and then Other the times I won't be able to read my graph because of the interference while im running the tm

My Foretrex 80 does the same thing, I have the universal. I thought it was me.

If you can't find any information to resolve this issue take a hour or two and consult a radio professional in your town. As in someone who deals with the cb's and communication networking. Depth finder is simply a radio frequency and is easily interupted by "noise" from your trolling motor. These guys deal with these same type of issues every day. Mainly on DC circuits too. If you need a good reference, contact your local sherrifs dept and see who is on their vendors list. Without a doubt, they will be able to clear this up. Or at least give you some good pointers.

I have a 1198 and Minn Kota TM that had no issues with interference until the shaft cracked. I took it to All-Star and they replaced the shaft, armature, brushes....etc and since then the screen fills with noise while TM is on making graph unusable. I have taken it back twice and have seen no improvement. I have taken to another service center to see if they can get anything resolved. Before taking in back to All-Star the second time I installed the TM choke that made the issue worse, ran new wiring to graph, ran ground wires to TM, grounded skeg on TM. All this made no improvment.

Again, go see someone who knows about radio noise interference. Not a trolling motor shop.

Nothin against trolling motor shops. I know there are many of em out there who definatley know their stuff.

Thanks for the info Claysefus .

Thanks for everyne's response. It is a 788ci combo and on the cranking battery not the trolling motor batteries. For those that are interested I will repost with solutions as I continue to try and resolve this issue. Last night I talked with Humminbird again and the are sending a heavier sheath power cable and I ran all the updates of course they are out of stock until the 2nd week of October. We'll see.