Smoked My TM Foot Control

[gunsinger]

So there I was, chasing schooling bass on a semi-windy day.  Every now an again, I'd smell what seemed to be an electrical burn.  I thought perhaps it was coming from someone's house until I saw the smoke coming from under the foot pedal.  I took a closer look and the hot wire was melting.  

 

 

I found that if I kept the TM speed control at 3 or less, no smoke. At 4 it would start to smoke after about a minute.  At max speed (5), it started smoking after about 30 seconds.  My first thought was that, for some unknown reason, the motor was pulling more amps than the wire could handle.  That may be the cause thought I cannot imagine why.  I pulled the prop to check if there was excessive build up of fishing line or something.  There was some line there but not so much that it inhibited the turn.

 

 

Some have suggested that perhaps the hot lead was loose and cause the damage.  I would welcome any input y'all can provide as to possible causes.  I've ordered a replacement switch and will have to get some wire to splice in (soon as I figure out the gauge needed).  But, I'm worried that I have deeper issues.

 

This is the hot lead after it broke off of the switch.

 

 

This is a MotorGuide x3, 45lb thrust, 12v system with 2 12v 92ah batteries wired in parallel.  I have a 50 breaker on the hot line back in the battery compartment as well as an inline fuse.

 

Anybody have any thoughts on what may have happened?

 

TIA,

JR

 

 

[Tennessee Boy]

I would think there was a problem with the lead.   Corrosion or any bad connection that increases resistance will cause heat. Your breaker should be sized to throw before things start smoking.  

[gim]

It pays to regularly take the prop off your trolling motor.  I just did that the other day and the amount of crap built up in there was amazing because I had just done it 10 days prior.  No fishing line, but a lot of stringy-type weeds.

[Deleted account]

48 minutes ago, Tennessee Boy said:

I would think there was a problem with the lead.   Corrosion or any bad connection that increases resistance will cause heat. Your breaker should be sized to throw before things start smoking.  

That would be my guess too. Inspect the wire and other side terminal, and if you have the slack, cut off an inch and crimp a new terminal, also check the connector, as it may also have been compromised, and it will most likely require a few passes with emery cloth to reveal bare metal, or maybe more, while you are in there check all the connectors. I gotta do the sequencers on my air handler before the heating season, same idea, more voltage...

[casts_by_fly]

same as above, but I'd go one step further and put a little dielectric grease on the connections when you put them back together.  Anything electric and exposed to water and elements has a hard life.  A little dielectric marine grease will help keep the water and air off the connections.

[Woody B]

I suspect the switch was the point of failure.  Heat started due to high internal resistance in the switch.   Is that the MOM-CON switch?   A friend of mine had that switch fail on a (27 year old) Motorguide a couple weeks ago.  I gave him the Edge that I took off my boat when I installed my Terrova.   

[TnRiver46]

I’ve started a small boat fire or two with a trolling motor 

[gunsinger]

1 hour ago, Woody B said:

I suspect the switch was the point of failure.  Heat started due to high internal resistance in the switch.   Is that the MOM-CON switch?   A friend of mine had that switch fail on a (27 year old) Motorguide a couple weeks ago.  I gave him the Edge that I took off my boat when I installed my Terrova.   

Yes. That’s the switch. I’ve ordered a replacement and some AW6 to replace the damaged wire. I plan to solder the tips on and use the marine grease recommended above. 
 

Thanks for all the feedback.