Why do Trolling Motors Fail ?

[fucawi]

When your motor packs up what do you find was the cause ?
Water gets in through the seal ? After how many years?
Brush failure? Do you replace and carry on ?
Controller contacts /Electronics ?

 

[John_S]

Re: Why do Trolling Motors Fail ?

I haven't had one fail where it was inoperable. Never had to open a motor up to see if it was brushes or water. I have bent a shaft on one, that makes using it a bit more "fun", and had corroaded battery connectors on another. My dad had an old Herter's trolling motor, about 15lb thrust. Used it when I was a kid, and was the locomotion we had for 17' canoes. The contoller wore out in the 90's and he replaced it with a switch. I got him a new 30lb in the late 90's. Knowing my dad, it is stored somewhere with a still operational motor.

We live in a disposable society. Few people take the time to figure out what is wrong, yet alone fix it. As soon as the prospect of shipping, diagnoising, fixing, has any likelyhood of reaching 40-50% the cost of new, its trashed. Some assume its broke, it WILL cost too much to fix.

From being here a number of years, the reported problems that make it to this forum, seem to be the digital controlled units. Much more than simple speed coil models. Even on digital controlled, the controllers, FETs, foot control failures seem to outnumber motor failures by far.

 

[fucawi]

Re: Why do Trolling Motors Fail ?

Thanks for the time to reply ..I did have one I left on the shed floor ..horisontal and it rained ....6 inches ofwater in the shed ( thats australia for you) and water got in via the shaft tube ...quick clean and she was ok ....keep everything 12 in above the floor from then on !!!!
Seems they are as reliable as starter motors .....

 

[Silvertip]

Re: Why do Trolling Motors Fail ?

Motors generally fail for the same reasons outboards, inboards, and I/O's fail. The words that come to mind are "abuse" and "neglect". They run through sand bars, hit stumps, rocks, and wrap weeds and fish line around the prop. shaft. They run the battery down to zip and wire them poorly. They leave foot controls out in the elements, and stomp them to death. When the motor does begin to show signs that something is wrong they continue to operate them until they finally die and then wonder why.

 

[fucawi]

Re: Why do Trolling Motors Fail ?

Interesting .....83 views and not a clammer of people saying water go in it or brushes ..so we deduce the bit under water is good and bullet prooof if you check for fishing line occasionallly .....any more information ??

 

[Silvertip]

Re: Why do Trolling Motors Fail ?

Except for tournament fisherman, I can't imagine brush failure as a reason for untimely death of a trolling motor. They will generally outlast the owner of the motor. It is certainly possible but I would liken that to a 20 year old person falling over from a heart attack. The body of a 70-80-90 year old falling over from a heart attack would be considered simply "worn out". Water inside is certainly a common failure but as pointed out, is primarily due to seal failure due to the aforementioned abuse/neglect. I did not include electrical foot control and power cable failure but those do not cause failure of the motor -- failure to operate yes, but not damage to the motor itself.

 

[MH Hawker]

Re: Why do Trolling Motors Fail ?

From what I know of them thier are no brushes, and the rotor and bearings and seals are the only part in the bottom and the shaft seal is the thing that wears out and lets water in, I have replaced a few. The motor is oil filled with transformer oil I belive for insulation


fishing line in the prop shaft seal is that kills them

 

[mxfever]

Re: Why do Trolling Motors Fail ?

I'll throw a curve ball on things. I bought my trolling motor used. Its a Minn Kota 90T XL- 40lbs of thrust. I was on my second summer of use when it all of a sudden quit. It would run if you picked it up out or water but as soon as it was in the water/under load it would stop. Battery was still over 12V.

Ended up tearing into it and knew it wasn't good as soon as the prop came off. Fishing line was wrapped around the shaft just under the prop and the seal was starting to come out. Pulled the end of the motor off and it was FULL of water. I took it all the way apart and found both brushes cracked.

I now know what to look for when buying a used trolling motor since I've never had my line get tangled, it was already there and probably damaged when I bought it.

So, if anyone has a lead on where to get rebuild kits I would love to know what parts are going to cost.

 

[Silvertip]

Re: Why do Trolling Motors Fail ?

You can check the MinnKota web site for a list of their Service Centers. You get parts from them. Except for props and foot controls, you won't likely find internal parts at marine outlets.

 

[fucawi]

Re: Why do Trolling Motors Fail ?

No brushed and oil filled is In think a fairy land suggestion but I wish it were true !!!!..AS for parts well drying it out in an overn at 50 deg C and maybe a re varnish ....clean or turn the commutator on a lathe and if you cannot get brushes then motor brushes are easy filed down to fit But not starter motor brushes as they are too hard ..must come from a motor that runs continuously or a dynamo ( generator) ...on many a card tube holds the brushes apart and when you push in the armature it just falls out ...so it does seem fishing line and damaged shaft seal is the problem....anybody tried this ......model areo propeller ....

 

[mxfever]

Re: Why do Trolling Motors Fail ?

Well I was poking around the internet at lunch yesterday and stumbled onto this site.

http://www.northlandmarine.com/MinnKotaQuickRef.htm

$35.00 for what I need isn't bad at all.

 

[John_S]

Re: Why do Trolling Motors Fail ?

What are said advantages? Very little blade area, would think it would not do well accelerating a heavy boat from a stand still. ie for a fishing, positional trolling motor. On a light, electric only, maybe some efficiencies there. Given the the thru hull mounting, and shaft housing, it is probably the latter.

 

[fucawi]

Re: Why do Trolling Motors Fail ?

quoted as 88% increase in range at 4 kts compaired to the origingal Minn Kota prop.Every body is skeptical until they try it ...drop the revs from 10 000 on the plane to 800 on a boat and consider the medium change from air to water and there you have it .....
You need to look at www.boatdesign.net for full details try 10 x8 for starters....

 

[John_S]

Re: Why do Trolling Motors Fail ?

Yea, with those type of numbers, I'd be on the skeptical side too. I'd want to see the amp reading at 4kts for both props. If I had electic only restrictions and had larger range needs, might be more interested. If I ever modify one to use on my kayak, and want to keep the battery size to a miminum, ie smaller battery but get same range, might be take another look.

 

[TerryMSU]

Re: Why do Trolling Motors Fail ?

No brushed and oil filled is In think a fairy land suggestion but I wish it were true !!!!..AS for parts well drying it out in an overn at 50 deg C and maybe a re varnish ....clean or turn the commutator on a lathe and if you cannot get brushes then motor brushes are easy filed down to fit But not starter motor brushes as they are too hard ..must come from a motor that runs continuously or a dynamo ( generator) ...on many a card tube holds the brushes apart and when you push in the armature it just falls out ...so it does seem fishing line and damaged shaft seal is the problem....anybody tried this ......model areo propeller ....

They do make brushless motors for computer cooling fans. Basicly, the motor is a simple AC motor and the electronics converts the DC to low voltage AC. I am not sure what the limitation is as far as horsepower, but I suspect it is quite low. Interesting thought though. As far as the oil filled, probaly not, the losses due to the oil viscosity would be too low. However, brushless would allow you to seal the daylights out of the motor armature and coils. In fact, I suspect that the magnet is in the armature and the coil is on the outside for brushless DC, but I am not sure.

TerryMSU

 

[fucawi]

Re: Why do Trolling Motors Fail ?

limited Hp no ....4 + hp and about 3 in dia ...if you have wires going to it and spinning parts then you still have the same sealing problems...look at the motors on www.hobbyking.com the controller turns the DC to 3 phase AC and yes the armature is stationary and the case spins ...are being used to power boats and as micro 12v @ 10 A generators driven by brush cutter motors

 

[kahuna123]

Re: Why do Trolling Motors Fail ?

When I owned my shop.
MG failed because the variable speed electronics were crap.
Most older motors failed because of shaft seals leaking
Some just began to run poorly from lack of service. Brush dust accumulating in the windings.
Some of MK were ruined after water intrusion as the epoxy holding the magnets in place gave up when wet.
Bad connections in the high amp circuits was always a problem.

Motors never intended to be NEAR salt water were used in the wrong environment.

 

[fucawi]

Re: Why do Trolling Motors Fail ?

...Quote Most older motors failed because of shaft seals leaking


so we are back to a spot of oil seal expander on the seal particulary after a couple of seasons..