Minn Kota 30 lb. Endura Teardown Question

[Zach Matthews]

Guys I am having an issue with my Minn Kota 30 lb. thrust transom-mounted trolling motor. This motor hasn?t seen much use, but I found it almost new on the bottom of a river several years ago, so it definitely got flooded at least once. I have used it dozens of times since it was flooded, fwiw.
My issue is that the motor only works some of the time. It started doing this late last year and I am just now getting around to working on it. I?ve popped the head off and cleaned all the terminals on the speed selector switch. That definitely helped restore top end speed when the motor *does* run. However some of the time when I set it into either forward or reverse it just sits there, until I nudge the prop. Sometimes nudging the prop kicks it into gear and sometimes nothing happens. Seems to be random.
This definitely feels like an electrical short situation. But is it in a wire? It seems to get power just fine when it is running and no matter how I twist the wires around I can?t short it out. Could it be the speed selector switch? I actually popped the positive and negative wires off the speed selector switch and ran them directly to the battery, testing all three colors (white, red, yellow), and I got the same random failure rate in terms of whether the prop worked normally or not, so I kind of think the switch is fine. Perhaps the brushes in the motor head are corroded or something? (Again, this motor has seen pretty light use, so I don?t think those are worn down, but maybe they?ve got a short?).
I don't mind tearing electronics apart but I am not sure where to hunt here. Any help appreciated!
Zach

 

[gm280]

Zach-Matthews, :welcome: to iboats. Great to have you aboard...

I think your problem in in the foot, in the actual motor housing it self. So it is time to open it up and see what is going on there. The brushes may not be needing replaced, but there could be corrosion where the wires attach to the brush holders. So open it up, and check the brushes, commutator, wires, seals and bearings. Most all of those parts should be easy to find and replace if needed. And a good cleaning and such will get it back into business again as well. JMHO!

 

[Zach Matthews]

Thanks for the advice! You were absolutely right -- the seals on the lower unit had failed and it was full of corrosion and some thin mud in there. I scoured it out then soaked it for three hours in WD-40, cleaned all the parts and reassembled, and it appears to be working properly now. I probably ought to replace everything inside that lower unit eventually, though -- this might last a season but I don't see it lasting forever.

Two questions: (1) does Minn Kota sell like a lower unit kit I could buy? Assembly looks easy.

(2) What are your thoughts on me packing that housing with marine grease like a trailer hub in order to keep it from corroding again until I can get new parts in there? Obviously the seals have already failed once...

Thanks!
Zach

 

[fishrdan]

I doubt water got in the motor due to bad seals, the motor/shaft is open to the atmosphere and if the thing was dunked in the river, water got in through the shaft.

Still not a bad idea replacing all the seals anytime the motor is opened and I would definitely replace the ball bearing on the shaft, brass bushing should be A-OK. Take the armature and place it in the oven at loooow heat (150*) for a couple of hours to drive out all the water, then re-lube and assemble the lower unit. The switch should be replaced, corrosion. You may try opening the switch and cleaning it out, but from what I've seen - - - the switches are difficult to reassemble...

Don't pack the motor housing with grease, or fill it with oil. For replacement parts, go to fish307.com.

 

[fhhuber]

The symptoms described are typical of a motor with a bad winding or a bad commutator. If the brushes are on the lands of the commutator for the winding that won't power up, the motor doesn't start.

That may or may not be repairable.

 

[gm280]

Thanks for the advice! You were absolutely right -- the seals on the lower unit had failed and it was full of corrosion and some thin mud in there. I scoured it out then soaked it for three hours in WD-40, cleaned all the parts and reassembled, and it appears to be working properly now. I probably ought to replace everything inside that lower unit eventually, though -- this might last a season but I don't see it lasting forever.

Two questions: (1) does Minn Kota sell like a lower unit kit I could buy? Assembly looks easy.

(2) What are your thoughts on me packing that housing with marine grease like a trailer hub in order to keep it from corroding again until I can get new parts in there? Obviously the seals have already failed once...

Thanks!
Zach

DON'T pack the foot with grease or oil or anything else. Just clean everything, commutator as well, and make sure the brushes, bearings are good and reassemble with good seals. It should run for a long time after that. JMHO!