mounting tranducer to elec motor?

[Mako]

I've recently mounted a transducer to my trolling motor. It's a minkota 756mxt, and my finder is an Eagle Ultra Classic.

I mounted the transducer to the motor with plastic tie straps, it seems to hold real well and doesn't move much.

The problem is that I'm not getting good reading at all from the finder. I always did when I ran off of the transducer at the back of the boat and used the motor from the back. Now I'd like to use the front chair and of course my fishfinder, I know others have done this with success but everytime I step on the footpedal I get like a spike or line vertically on my finder. Then the reading don't seem accurate.

I can still read bottom depth, but seems like the grayline is weak or not working and I know I'm not marking fish because my bottom bouncer won't show up on the screen when it's right below the transducer.

Does anyone know what the problem may be? Is it electrical interference from the elec motor?

I'm running the finder off of the same battery as the trolling motor, which is isolated from everything else on the boat.

Thanks to anyone who can help.

[Chairman]

Try insulating your td from the motor with a piece of rubber from an old inner tube. This keeps some of the electrical interference from the unit.

[Famous]

I would find a power supply from the main battery. 2 reasons. Less chance of interfearance,and your trolling motor will perform on a low battery but your sonar unit requires a certain amount of amps to keep functioning. So you my find yourself with enough juice to run the motor another couple of hours ,butnot enough to operate sonar unit.

[Paul H]

Minn Kota states to run a fuesd wire from the neg side of the battery to the hull - if an alum boat - if glass I'd try a common grounding point.

On my previous boat - mine did this - with later MK - it didn't do it.


My last MK came with the ground wire.


If your transducer cable is bad - does same thing - had 1 that I'd nicked the shield -

[REW]

Try an experiment -
Pick up another battery - a pair of 6 volt lantern batteries, an extra starting battery - or ?
Connect the depth finder to this battery and test the operation. I doubt that it will make a difference but it might. The other posting about not using the trolling motor for the depth finder is a good one - for the reason that they stated - the trolling motor can be used until the battery is 0 volts - however most depth finders need at least 10-11 volts to work properly.

The 2nd thing that you can try - is to increase the spacing between the transducer and the trolling motor. Pick up some shims - rubber, plastic, or even lead. Actually lead strips would be the best. You would like something to shield the electrical noise that is coming from the trolling motor from the transducer. Noise can be coupled into the transducer from any direction. However, if you get some distance from the noise source to the depth finder - it will help.

Try this experiment - with the transducer off the trolling motor -- simply mounted to a stick - have the trolling motor in the water and bring the trolling motor transducer closer to the trolling motor. With the trolling motor being turned off and on at various speeds - try different distances of the transducer from the trollling motor -- this will tell you very quickly if the problem is coming from the trolling motor -- and if so -- how far the transducer needs to be from the trolling motor to avoid the problem.

The problem that you are seeing -- is exactly one of the primary reasons why the pinpoint trolling motor was developed. The folks at pinpoint spent many years and a lot of money to come up with a system - that uses a transducer frequency, a power supply frequency, and a motor design, so that the two units don't talk to each other.

Good luck on your testing.

If you find that you need to be more than about 1/4 inch away from the trolling motor to avoid the noise and to get reasonablly good readings - the next best alternative - is to simply mount the transducer on the back of the boat and use that position for the transducer - and live with the slight loss of information that you get in depth - in reading from the back to the front of the boat. Another advantage of using this system - is that you will get good depth readings for the front depth finder at any speed and also if the trolling motor is in the water or not.

Good luck and stay noise free.

Take care

REW

[Mako]

Thanks to all for the information.

I'll try some testing this weekend and see if I can isolate the problem. The bad thing is, if I have to use the transducer at the back of the boat, it's permanently run to the dashboard, so I can't use it from the front of the boat.

Too bad eagle doesn't make a splitter for the tranducer cable, then I could run the same tducer to the front as well as the dashboard. I don't really want to mount another tducer on the back of my boat.

Thanks..

[carl]

It almost sounds to me like you have 2 problems 1)electrical interference and 2)the transducer may not be mounted to shoot straight at the bottom. Make sure that the transducer is fastened at 90 degrees to the shaft(or parrelled with the bottom). If it is not mounted so it is shooting straight to the bottom you are going to get some really silly and week readings. Also as the others have said - try insulating the transducer from the motor.

[John in MN]

LAST EDITED ON Jul-07-00 AT 11:17PM (CST)[p]What I did to get my transducer away from the motor (not because of interference, but to prevent bending the transducer cable at a 90 degree angle) was to make a spacer out of pvc pipe. I attached the pvc pipe to the motor with a large hose clamp and then the transducer to the pvc pipe with wire tie straps. My spacer is about 1 3/4 inches. My locator is a Zercom Clearwater Classic 2EL and the motor is a Minnkota 824 Autopilot.

[fishing protege]

i was having the same problem with my transducer so i got a high power suction cup and used that to mount it. all i had to do was remover the transducer when i took it out of the water it was a little extra work but it was cost effective and gave me a very clear picture of the bottom where ever i wanted to put it so i could move to anywhere in the boat and still know exactly what was under me. its worked for me and of course its just a suggestion but i like it and have no intention changing right now.

[John in MN]

Where did you buy the suction cup from? I need a new one for my old Lowrance green box. The suction cup has dried out since the 70s and no longer stays on the boat.

[Dodge1]

I used to run a Eagle, with the skimmer transducer, on my trolling motor. Eagle sells a trolling motor bracket, that fits the skimmer transducer. Worked like a charm and easy to install.

Check Cabelas, they have the bracket for $6.49.

You also need to run the finder, off your starting battery, IMHO.

[Don C]

I recently attached a flasher unit to the elec. motor and it's working well. I powered the unit with a motorcycle battery so it can be recharged and mounted the transducer to the motor shaft with a block of wood grooved to fit the shaft. The wood separates the transducer from the shaft approximately 2" so the bottom of the transducer is clear of the motor body. Clamp to the shaft with plastic ties and you have it pretty well isolated. Works well.

[John in MN]

My Zercom flasher was purchased for ice fishing. I use the small 12 v rechargable battery that came with it on my boat also. It is going on year six and still works great. No worries about how to run power to the bow.

[KM]

REW is right on, however, the best solution to this problem (if you find out that using the starter battery fower does not work)is to purchase the swing arm gunnel mount from Tite Lock. I have 2 transducers mounted to mine and it sits right to my right on the gunnel in the bow. It is the best way to keep the transducers near where you are fishing and remove any interference. I have absolutely none from mine.
Email me for more Info. :-)

KM

[KM]

P.S. - Try to stay away from any switches and try and always use direct lines to the battery or for the transducer. Creates less problems for corrision / resistance.

KM

[KM]

P.S. - Try to stay away from any switches and try and always use direct lines to the battery or for the transducer. Creates less problems for corrision / resistance.

KM

[Mako]

thanks to all for the great ideas, there's lots of em. I'll let yous know how I make out.