MotorGuide Trolling Motor Wiring

[fishinwrench]

Great my boat has that switch.

The contacts in the switch are not heavy enough for 24v.

After the switch ages a bit and gets a little corrosion in it they'll heat up bad, and it won't trip the breaker back at the batteries until it melts itself into one of the ground wires....And by that time you pretty much have a fire going on.

[Muddy Water]

I would suspect a damaged power cable since it was about an inch from the plug. Vibration can cause the wires inside the jacket to break causing what is called a hot spot. I've worked in the offshore drilling industry as an electrician and vibration is a major problem with cables. I can't count the number of times that I've had to repair or replace cables due to internal damage; the outer jacket will show no sign of damage but when you cut it open you find several conductors or all of the broken. The cable is designed to be flexed but only for X number of times. An undersized cable will typically blister the entire length of the cable when over heated. A loose connection in the plug should show discoloration on the metal tabs and the plug itself would melt. Since the breaker did not trip that leads me back to the possibility of a damaged cable; broken conductors means less amp capacity which will cause a hot spot.

I would check for excessive movement in the cable when the trolling motor is being deployed or when the main motor is running, especially in choppy water. Not sure if this is what happened but it sure fits the description for what I have experienced

[GNSfishing]

Sounds like you had dirty pins. I hardwire my TM (no plug) because I have had that happen several times on plug connections.

Also, if your boat is equipped with a 12/24/Charge switch I'd bypass that POS, they have started more boat fires than anything else I know of.

No dirty pins, the contacts were all bright and shiny and tight in the receptacle. Not discolored even from heat from the 2 wires burning into. So the plug did not cause the the problem. As far as a 12/24 charge switch my Z8 is 24 volt only no switch. I did have a 1983 350 V Ranger that had such switch and that boat and switch is 32 years old and still has the same switch that came on the boat with no problems to this date..

I would suspect a damaged power cable since it was about an inch from the plug. Vibration can cause the wires inside the jacket to break causing what is called a hot spot. I've worked in the offshore drilling industry as an electrician and vibration is a major problem with cables. I can't count the number of times that I've had to repair or replace cables due to internal damage; the outer jacket will show no sign of damage but when you cut it open you find several conductors or all of the broken. The cable is designed to be flexed but only for X number of times. An undersized cable will typically blister the entire length of the cable when over heated. A loose connection in the plug should show discoloration on the metal tabs and the plug itself would melt. Since the breaker did not trip that leads me back to the possibility of a damaged cable; broken conductors means less amp capacity which will cause a hot spot.

I would check for excessive movement in the cable when the trolling motor is being deployed or when the main motor is running, especially in choppy water. Not sure if this is what happened but it sure fits the description for what I have experienced

Now you could be on to something with a bad spot in the wires at the plug but the plug and wire are so short and confined within the the foot pedal well and that the wires are inside a sheath which contains the wires providing support with no room to flex from running in choppy or rough water. I bet that I haven't even unplugged it a dozen times or less since the boat was new. It is just now 5 years old, could've been a bad installation don't know that. I've come to the conclusion that with a motor that could draw up to 50 amps through a wires rated for 30 amp is asking for trouble in a prolonged run in high speed for any length of time and that's what I told the MotorGuide people on the phone..

Every 24-volt MotorGuide I've owned has been prone to pop breakers if you stand on the pedal too long. I now have a 36-volt Minn Kota Fortrex and haven't had a single issue with that (or anything else).

Apparently the breakers were too small. I remember when Minn Kota first started selling trolling motors that they had a bad failure rate with the magnets breaking in the motor. I knew several guys that had that problem with the Minn Kota. Of course they all have shortcomings that can and do crop up at the most inopportune time.

Thanks to everyone for their insights on the problem I have with my trolling motor. I am going to troubleshoot the amp draw when I get a AC/DC clamp on amp meter. Then I'll know what the real current draw is and size wire and breakers to their proper size and/or take it to Marine Repair for motor work if the board is the problem in the motor.