Trolling Motor Problem...need Help

[Frogman]

My boat has been sitting up for around a year due to a military deployment. So today was my first real chance to get out and really work on it. I had a motor guide on it that has an issue, so instead of addressing that issue I decided to put another one on it. I have a Minn Kota All Terrain 55lb thrust that has been sitting in the shed for about a year. It worked fine when I discontinued use of it. Well I mounted it to the boat and plugged it up. Nothing. Here is what I know. It does not work in MOM or CON. I have a good battery and have voltage at the plug. It is a two wire system from the plug to the pedal. I can read voltage across these two wires until you attempt to run. The voltage then drops to 0, let go and voltage goes high again. What could be loading my motor? Am I wiring this correctly? Red to 12VDC and Red/Black to GND (Yes it is a 12VDC motor)? If anyone has any advice or has seen this issue before, please let me know.

[Traveler2586]

Do you still have the manual? If not here is the PDF http://www.minnkota....All Terrain.pdf

Sounds like you have a short somewhere between the switch/ 5 speed control and the motor, or the motor is not starting it's rotation and the voltage drop you see is the "locked armature current" draw.

Does the prop spin smoothly & easily??

Have you checked using different speed control settings?

Carefully inspect the wiring in the foot control up to the TM's head for possible problems. Look for signs of corrosion.

Try using the Ohm meter function to check for a possible short. There is a Black, White, Yellow, and Red wire going to the TM's head. Meter between the Black wire to each of the other wires to check their function.

The wiring diagram is not complete as far as how the Red, Yellow, & White wires connect in the motor housing so I can't say more on that.

Try working the speed control through all of it's setting repeatedly in an attempt to clean the wipers in the control, they may have corroded while setting idle.

Also, try rotating the prop in an attempt to clean the armature and it's wipers of any possible corrosion.

[Frogman]

Thanks for the response. I am still chasing the problem. All of the wires in the foot control and anything else I can see look great. No corrosion at all. This thing practically still looks brand new. I went through all the speed controls and settings and even did it again tapping on the switch and the relay under the pedal to see if I could "unstick" something. No luck there. The prop spins very smooth, I decided to pull the motor just to see if there were broken windings or bad brushes or anything visiibly wrong. The armature looks good, bearings are smooth, brushes still look brand new. No rust or corrosion at all. With the armature pulled from the system my short between PWR and GND goes to 8 ohms rather than 0. I know that doesn't really tell me anything as I have completely changed the circuit and 8 ohms is still a dead short. Just letting you know my observations. I have not popped the top part off of the motor, as I am a little nervous as to what I will see. Judging by the schematics you posted, All i see is moving parts. Are there electrical parts in the top, or do the wires just move through there and on down to the motor?

[Traveler2586]

It's difficult to say the best way to test with just an "assembly" schematic as opposed to a "circuit" schematic, and I have not seen this TM myself. Some times the head will have a light/LED so you can see the pointer at night, and there may be connections between the flex cable coming from the foot control and the shaft wiring going down to the motor. However, I don't see any parts listing for a "Head" connecting block (or they could just use in-line quick connectors) and I don't see any listing for a motor shaft cable.

Probably at this point the most prudent step would be to call a local service center and discuss the problem with a tech rather than the front counter staff. A tech can tell you the most seen problem areas for your TM and give you an estimate cost to repair it.

[Frogman]

Well here is the update...... I almost feel dumb. My buddy came over and he suggested that before we even start trying to get further into this thing we should rule out the boat completely and hook the TM straight to the battery. I argued with him a little bit and told him that I had voltage at the plug, that told me that everything was good as far as the boat was concerned. Well he won and we did it. The trolling motor runs like a brand new one. As a said the boat had been sitting up for a little while now. There was a bad connection inside of the front panel behind the female receptacle. The connection looked good and would pass voltage but the wires had rusted right there and apparently would not pass the current needed to run the TM. We have replaced the connection and I am about to go stick her in the water and see what other issues I need to address. I think I am going to re run the wires for the trolling motor completely once I get back to avoid any future issues like this. I really appreciate your help and advice!

[Traveler2586]

Congratulations on your find, I'm glad it wasn't anything more.

If your going to re-run the wires think about using #6 flex wire ( something like wielding cable, soft and supple ) and don't forget a marine circuit breaker close to the battery.

Again, congratulations, and good fishin'