Finicky MotorGuide trolling motor

[Steves62]

Hi guys. I'm new to the forum but not new to fishing and boating. I apologize now for the long thread but I wanted to get all the facts out there.

I have a MotorGuide W55 wireless trolling motor. It's about 3 (maybe 4?) years old. The battery for it is nearly brand new (not the issue, I guarantee it).

Symptom: Occasionally, when hitting the 'on' switch on the foot pedal, the propeller will not spin at all, regardless of the speed setting -- it could be really low or really high or anywhere in the middle. A simple flick of the propeller with my finger will get the motor moving. If I then hit 'off' on the foot pedal, the motor turns off just fine. I let the propeller come to a full stop. At this point, if I hit 'on' again, I have about a 70% chance that it will actually spin again. The other times, it just sits there and, again, will spin only if I nudge the propeller along. I will mention that the power steering of the unit is fine -- smooth, full rotation, good speed, etc. The problem is all in the propulsion. Also, there is nothing trapped between the prop and the lower unit housing; no weeds, no fishing line, etc.

My suspicion is that I have some bad brushes or something similar to that. This problem first cropped up last year and I attributed it to winter (indoor) storage and just a long period of non-activity. However, it cropped up again this year (again, after indoor winter storage). I should also mention that when the propeller is spinning and the power is at max, I don't feel like I'm getting full power from it. This has been true the last 2 years -- same period of time since the first issue with the motor not spinning. In fact, last year when I first tried to use it, the unit felt as if there might have been some sort of corrosion inside of it. It was that hard to spin by hand (almost like it had locked up over that period of non-use).

I would LOVE to pull apart the lower unit (appears to be only held on with 2 long bolts) but without an exploded parts diagram or shop manual, I don't want to face an explosion of springs and brushes.

If anyone has any insight on where I can find a disassembly process or parts diagram, I would be much obliged. I'm very capable of fixing things but I also know when I'm crossing into the "I might not be able to get this back together again" territory. I'm also curious as to whether or not anyone else has had troubles with these motors. Again, I feel like there may be some seal problem, too --- that may have been the root cause of the initial problem (nearly seized propeller shaft).

 

[John_S]

Re: Finicky MotorGuide trolling motor

You can search on "Motorguide Wireless Parts Diagram" and find a few sites. Here is one:http://www.boats.net/parts/search/Merc2/Motorguide/MotorGuide%20Wireless%20Series/9B920032%20%26%20Up/Lower%20Unit%20Assembly%2855%23%20-%20Variable%29%20%28FW55%20Black%29/parts.html

Your description does sound like brushes or corrosion, but probably not going to know until you open it.

 

[Steves62]

Re: Finicky MotorGuide trolling motor

Thanks, John! I did a search like that and struck out. You had much better luck. This gives me much more confidence about reassembly.

I won't be ordering anything until I have a chance to get back to the boat and that won't be for a couple of weeks. But at least I'll be able to get my exact model number at that time. And I see they offer a "repair kit" for each model. I'll look into that to see exactly what's included.

Next step: Disassembly. Love it!

Thanks again.

 

[John_S]

Re: Finicky MotorGuide trolling motor

Thanks, John! I did a search like that and struck out. You had much better luck. This gives me much more confidence about reassembly.

I won't be ordering anything until I have a chance to get back to the boat and that won't be for a couple of weeks. But at least I'll be able to get my exact model number at that time. And I see they offer a "repair kit" for each model. I'll look into that to see exactly what's included.

Next step: Disassembly. Love it!

Thanks again.

As a wireless owner, I would be interested in anything you learn from the process. Pictures during the dissassembly would be great.

 

[Steves62]

Re: Finicky MotorGuide trolling motor

Guys --- I just realized that I never finished up this thread. I took the motor apart and found a significant (to me) amount of corrosion and oxidation in there.

1. The copper contact area of the armature (part #20 on the diagram above) where the brushes ride was black from oxidation; I'm sure I was getting less-than-perfect electricity flow, which certainly explains the lack of power.
2. The exterior surfaces of the armature (not the copper winding but the bars -- for lack of a better term -- that run parallel to the motor's shaft) had surface rust on them.
3. There was a fair amount of surface rust (more like surface dust) on the sleeve (part #24) that houses the mega-magnets, too.

How did all this corrosion/oxidation occur? I don't know. This motor is only 3 years old or so and has not been abused in any way. The boat is stored indoors so the motor only sees weather and water when the boat is used.

Basically, all I did was a thorough cleaning and then careful reassembly.
Specifically...
-- I cleaned up the armature bars using my bench grinder fitted with a wire wheel.
-- Ditto for the copper contact area.
-- I thoroughly cleaned all remnants of corrosion / oxidation from inside the housing and from inside the sleeve.

I did NOT replace any of the seals or O-rings. I *did* apply silicone grease to all O-rings (part numbers #2 and #29) and to the shaft seal (part #26) but I didn't actually remove the shaft seal itself. After the thorough cleaning and reassembly, the motor really runs well. There's no more hesitation starting (even at a very low speed setting) and no unnerving scraping sounds. Honestly, it runs like new.

I apologize for not taking any pictures but, honestly, it's FAR from rocket science. HERE ARE THE STEPS THAT I TOOK:

DISASSEMBLY
Remove the propeller; don't lose the shear pin.
Remove the two bolts (part #28) holding the rear cover on; pay attention to where they were in terms of imagining the rear cover was the face of a clock. These bolts screw into the nosecone and those hole locations will not be changing.
Remove the rear cover.
Pay attention to the shaft washers (part #'s 22 and 23) to be sure they go back on in the same sequence that they come off.
Note the orientation of the sleeve surrounding the armature; there are two manufactured gaps in the magnets, allowing the bolts that hold the entire lower unit together to pass by. Make a note of how this is aligned.
Now, remove the armature and the sleeve with the magnets (part #s 20 and 24) as a unit. Due to the strength of the magnets, this will probably happen on its own anyway.
The brushes (part #17) are mounted to a plate (part #15) and can be left alone. Just be sure that they operate smoothly; there will be small springs pushing them to stay in contact with the armature's contact area.

You will need to use some force to remove the armature from the sleeve with the magnets that surrounds it. I'm not talking about a hammer but I am talking about a surprising amount of arm force to overcome the magnetic pull. If you've not done it before, it's quite surprising!

Clean everything thoroughly, removing any oxidation / corrosion.

On reassembly, I used some inline skate bearing lube at any point where the motor's shaft contacted another surface. That would be at the nose (ahead of the copper contact area) and also where it passes through the rear shaft seal.
As I mentioned, I used silicone grease (plumbers use this on O-rings) for all O-rings.

REASSEMBLY
Install one of the larger O-rings onto the rear of the nosecone housing (part #4) after lubing the O-ring generously with the silicone grease.
Apply some inline skate bearing lube to the motor shaft of the armature at the front of the copper contact area.
When you go to install the armature into this nosecone housing, you'll have to get the brushes out of the way. An extra pair of hands, along with two thin screwdrivers, will work great to gently hold the brushes back while you seat the nose of the armature.
Holding the armature in place (keeping forward pressure on it), slide the sleeve holding the magnets into place, paying attention to the orientation. FAIR WARNING: The strength of these magnets will pull the armature right out of where you seated it so use force to keep the armature in place and apply some resistance to the sleeve as you seat it so it doesn't slam into place (or onto your fingers). Once the sleeve is in place, you can use it to hold both it and the armature in.
You will need to align the gaps in the magnets so that the long bolts that hold the entire lower unit together can pass by the magnets and screw into the nosecone.
Put on your next lubed up large O-ring.
Reinstall the shaft washers (I used the inline skating lube on these, too)
Reinstall the rear cover; I used silicone grease on the two small O-ring like washers on these, too.
Reinstall the shear pin and the propeller.

Hope that all helps!
Steve

 

[TerryMSU]

Re: Finicky MotorGuide trolling motor

Most of your black oxidation/dust was likely dust from the brushes. Cleaning it out and lubricating everything is what I would have done as well. While I have not pulled apart a trolling motor before, the dust you were seeing is not surprising. By the way, several years ago my dad pulled a trolling motor apart and we never go it working right again. I think that the cause was in how/where the magnets were installed, so I would be VERY cautious about pulling the magnets out of the motor. I would think that with the exception of your comments above, everything should have been relatively straight forward.

TerryMSU

 

[Steves62]

Re: Finicky MotorGuide trolling motor

Thanks for the comment, TerryMSU. Just to be clear, the magnets are an integral part of the mid-section of the lower unit housing. In other words, they are welded (at least it looks like weld marks --- I don't know if you can weld magnets) to the mid-section. Nothing comes apart with part #24 so there's no way to screw it up

If most/all of the black oxidation/dust was from the brushes (and I'm not saying it wasn't), that's really amazing! Based on the size of the channel in which the brushes ride, I'd say they were MAYBE 20% used up. I can't imagine how much dust there will be when the brushes get to the end of their useful life.