Home › Forums › Bass Cat Boats › Trolling Motor interference related question
Jstew.
I have a 2016 Cougar AE. I bought it with dual Hummingbird 788ci HD units on it. I did not have any issues with the original set-up, worked great! I recently replaced the bow unit with a Garmin echoMap 93SV with GT52 Transducer. I have a Motorguide 24V 75 lb. Digital trolling motor. I installed the Garmin unit this passed Friday. I tied in the Garmin unit in the same location as the Hummingbird unit was. I soldered the connections and used shrink wrap over the soldered connections. I also ended up adding another separate ground cable that went from the transducer clamp to the Garmin unit ground wire. When I activate the trolling motor above a setting of one and below 8, I get nothing but interference. I used a multimeter last night and ohmned out between the ground terminat on the trolling motor batteries and the ground on the starter battery. They do NOT share a ground according to my meter – should they? I am just wondering (desperation 🙂 ) if I dropped a wire off of the trolling motor set-up when I re-connected it to the batteries.Your help would be appreciated!Kevin
http://www.bbcboards.net/forumdisplay.php?f=128Might try over here as well.
Ive got the same trolling motor and what I did was run a ground from the sacrificial anode bolt with a crimp terminal to the ground wire bundle in the Motorguide head. Essentially they call it shunting the ground from the motor case. Tying in to the transducer clamp isnt a metal to metal contact. The unit should have a ground strap internally – but, if youre getting that kind of interference – its not making good contact. I ran nothing to the sonar unit and kept the power lines clean to the sonar. No they really shouldnt share a ground at all – its essentially a separate electrical system from the trolling batteries. ALL of the digital trolling motors are “dirty” with RFI and can cause issues. Minnkota uses an internal fused wire that works well until the fuse blows – then the sonar turns to snow…. No brand is superior in that regard – if its digital, you may be chasing some gremlins.I also didnt run my transducer cable down the Motorguide steering / power bundle. I ran it up the trolling motor shaft to the mount – then it separates off and runs down the mount and across to the sonar. Small adhesive zip tie lugs work like a champ to secure the wire. For some reason, running it down the bundle may give it too much opportunity to pick up RFI from the power wires inside.
jstew – GREATLY APPRECIATE IT! The sacrificial anode bolt is where? I dont recall see one. I presume that it is on the motor housing? I didnt think that running the extra ground wire off of the transducer clamp was going to help, since it is stainless steel, but as I said, I was desparate :-). I was willing to try anything.
The anode on the trolling motor should be a small disc on the back edge of the skeg. Its a 1/4″ flat head screw that holds it in place. A crimp lug on the end of the wire does nicely. You may want to sand the connection point to ensure good contact. When you remove the top of the trolling motor head, there are ground wires with a fairly large crimp connector to hold them together. A little work with a set of crimping pliers will get you enough slack to get it off. Get another of these connectors from your local trolling motor shop – btw, I tried a lot of places to find an insulated crimp large enough and it may be a motorguide specific part. Tie the wire from the foot to the ground loom, new crimp, and youre done. That “should” ground the foot and eliminate a lot if not all of your interference. You may also have to look into the noise filters on your sonar. With the 788, it was probably set to noise filter 3. That one is the magic number with them. I dont know what Garmin does with internal noise filtering and would be a call to their customer service is this doesnt do the trick.Most all of todays units have some type of interference issues. Motorguide will tell you they dont make sonar units. Garmin will tell you they dont make trolling motors. A few owners are lucky and have no issues – most arent so lucky. Sometimes it takes a few applications of snake oil till you find the one that does the trick for your particular issue. Good luck finding yours…..
I had issues with mine. The way cured the problem is kinda hard to explain. Actually found a diagram online though. I tried chokes and various things with no results. I ll try to explain. I went in the rod lock on the drivers side and found the ground running to the front. I cut the ground and hook another ground with the oringinal ground going to the front . The extra ground I ran to the tranducer clamp screw. Im fairly knowledgeable of DC voltage.but still dont full understand how it cured my problem with interference but it did. Cut midship and adding a ground with the oringinal ground. I know it sounds crazy! But it worked. Search around on the net looking at images and you will find the diagram. Because I know my explanation probably sound absurd!2013 PANTERA 2MERCURY 200 PRO XSMINNKOTA 80LB FORTREX25 fury
Appreciate it, but I had already tried that. I ran a separate ground wire to the transducer clamp. It helped a little, but very little. I did find a YouTube video that showed this to me. I knew that I could try that quickly.
I know the viedo your talking about. I to tried it that way. It didnt help. Until I cut the ground midship and tied to it and ran to the front did I see a change. I will add wat works for one may not not work on another. Many have used the chokes with success they made no difference with mine.2013 PANTERA 2MERCURY 200 PRO XSMINNKOTA 80LB FORTREX25 fury
Jstew – my MG does not have an anode where you describe. They must have change it in my model. The skeg is cast as part of that section of the motor housing. There is no external screws on any part of the motor housing on mine.
If you dont have a good mounting point – like the anode on mine, then it must have the internal grounding shunt. Do you have a MG shop near by? They need to make sure the case is properly grounded. Be fairly cheap to get them to open the unit. The ground shunt is only about $3.Without the various snake oil treatments – place a call to John Jones @ Jones Trolling Motor in Hope Arkansas. Hes one of the most knowlegable I know of when it comes to these electronics and both brands of motors. See what he has to say.
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