trolling motor problem

[Cevin c Taylor]

I posted up a while ago about getting a 30 lb thrust trolling motor for free for my 83 cp 16.  I finally got to try it out this weekend on Burt Lake in northern Michigan.  Since this was just a test, I clamped some jumper cables on my marine battery in the forward part of the cabin, and ran them out the companionway back to the rear of the boat.  The motor has two rusty alligator clips coming off it.  I clampted those onto the ends of the jumper cables, and the motor fired right up, and ran very noislessly.  A couple of minutes after starting it, I noticed that there was smoke coming off the base of the alligator clips that I had hooked onto the jumper cables.  In fact, it started to melt the rubber (or plastic) covers on the base of the alligator clips.  Fortunately I had the things sitting on a towel, and it did not damage my cockpit seat.  However, I'm confused as to what would cause this.  The jumper cables are probably 8 or 10 gauge, and should have no problem handling the capacity from the marine battery.  The cord coming out of the trolling motor is the original one, and presumably sized correctly by the mfgr.  (It's a "MotorGuide" brand).  My only thought is tha the rusty alligator clips provided a lot of resistance, and that that was the cause of the overheating.  I'd like to keep using the motor, but not if it's going to be a safety hazard.  Would cutting off the rusty clips and putting a plug end on it likely solve this?

[jgsharpe]

You are on the right track, that rusty connection would appear as additional load

[kickingbug1]

     i would try it in your driveway the next time. when you do put your hand on the motor (careful of the prop) while its running to see if the motor gets hot. could be a problem with the brushes or the bearings in the motor that is causing the resistance. possibly the speed control as well. the motor should not be hot.

[MacGyver]

Electricity on DC needs a very clean path. I deal with 450 Amp lift motors on our lift at work, and the connections corrode over time, I have since made a new setup completely rewiring them and the winches ran like brand new.
Anytime I get into electrical stuff I almost always end up replacing the wiring for one reason or another, and most times connections as well.

Dont know how handy you are, but I got a trolling motor one time, took it apart and put new wiring in, new clips, and she ran like a champ....... it had been thrown away by PO.

I am always messing about with things normal people toss out.

But yeah, I do agree that next time run it in the driveway, I dont think they require the water to be run since they arent water cooled, and a 5 gallon bucket is how I run my outboards when working on them (Or I use muffs..) but I havent seen a troller with the need for water cool.

Mac

[CaptRon28]

The trolling motor will use less current spinning in air vs spinning in water. Less resistance. That could effect the test a drop?

[Salty19]

Agree..use a bucket of water in the drive to induce load.

Don't these things have fuses? 

[MacGyver]

I dont think so, I did that so long ago I cant remember, But also something else to add (I hope I get my terms right......) Is that under stress the electric motors can actually burn up some, but that can be fixed (brushed motors are all I have worked on, and with mainly good results) By taking the motor out, and taking it apart, the spot that the brushes touch (commutator?) is all copper with some lines in it, The lines shoudl be clear of junk, and the commutator should be clean.
I have uses fine steel wool and 1000 grit sand paper to clean them, and cleaned the brushes also. reassemble with some grease in the bearing spots to renew the lube and good to go.
I have had a couple motors over the years go bad faster using lower grit sand paper, so 1000 to 2000 is the best option.

Wish I had some pictures to take of stuff I have done..... Just did my moped starter a few weeks ago...... turns out it wasnt the issue, but the starter was in bad shape.....

Mac

[CaptRon28]

I installed a 55 pound MinnKota on my Horizon last year - to occasionally use the boat on a local reservoir. I used a resettable hd circuit breaker in the wire going to the electric motor. Would have done this even if the Minnkota manual did not recommend it. It's got to be drawing 10 amps, especially in the higher speeds.

The motor mounts to an outboard bracket that attaches to the swim ladder, so the whole thing goes away fairly easily. Photo below.

[Cevin c Taylor]

Thanks for all the help.  I plan to take a look at the motor in the next couple of days. 
CaptRon28 - you said there is a motor mount that attaches to the swim ladder.  Is it visible in the pic?  I don't have a swim ladder, and I'm thinking of getting one.  It would be nice to be able to mount the trolling motor to it.  I've thought of just keeping the trolling motor stowed in one of the berths, to have it handy in case the outboard won't start.

[CaptRon28]

The motor mount is quite visible in the picture. Note the plywood bracket which clamps around the swim ladder. The stainless steel and plastic mount is bolted to it. The boat is a diesel, so it had no outboard motor mount and I did not want to drill holes in the transom.

[Cevin c Taylor]

OK - now I see it.  Thanks.

[Cevin c Taylor]

Update - yesterday I cut the rusty alligator clips off the end of the motor's cord.  I then used jumper cables to connect it to my car's battery.  I ran it for 20 minutes in my garage  (about 85 degrees), checking the temperature periodically.  The cord never felt hot at all.  The housing around the propeller heated up a bit, but not much.  It never got close to being too hot to touch or uncomfortable to touch.  I imagine that if it were in water it would have not heated up at all.  So, it appears that the rusty clips were the problem.  I'm going to put a male plug on the end of the cord.