# Thoughts on sealing the trolling motor shaft



## mwolaver (Feb 6, 2014)

Just bought a small TM for my boat. The shaft is open at the top. Having recently rebuilt a TM for my dad due to water intrusion in the motor, I question this design feature. The "head" of the TM also has vents; seems to be an easy trip for water into the controls area and down the shaft. 

So, I'm considering a temporary seal like silicon. I'm wondering if the motor heating and cooling is the reason for the shafting being open. What trouble I may be causing myself by sealing the shaft...

Any knowledge or opinions on this design or my seal idea are greatly appreciated.

Thanks,
Mark

EDIT: let me be more specific: I am worried about water getting into the motor via the length of the shaft, after getting into the TM head area....NOT the seal at the shaft to motor threaded connection.


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## mwolaver (Feb 6, 2014)

??


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## FishWithChris (Feb 6, 2019)

if it was supposed to be sealed, it would be sealed. 

TMs are left on boats for years at a time and rarely, if ever, have water intrusion issues. When they do, it is typically because they are not stored correctly while under way (vibrations, bouncing) or impact causing a break in the internal waterproof seals. 

which TM did you buy?


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## mwolaver (Feb 6, 2014)

Minn Kota. The "components" in the head area are potted. I sealed the 4 vent holes in the head pan, since my install will aim them forward under way. Will leave everything else factory. Thanks for the thoughts.


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## lappy18 (Sep 29, 2020)

I had the same question. Called mk today and the tech didnt sound too sure about water intrustion. i can see screws in there as well. Should this be covered????


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## finbully (Jan 26, 2013)

That unfortunately is a poor design. Won't see that on a Rhodan.


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## mwolaver (Feb 6, 2014)

lappy18 said:


> I had the same question. Called mk today and the tech didnt sound too sure about water intrustion. i can see screws in there as well. Should this be covered????
> 
> 
> View attachment 163834


Those are, in fact, the screws that hold the "top" on the head unit. The "vent" holes are the four, equally spaced holes much closer to the TM shaft. See one of them in the extreme left side of your photo.


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## MaGuyver (Nov 6, 2012)

NP1 Sealant or 4200? You could get a large enough bead to cover the gap and then let it set up. Both are flexible and could be removed.


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## lappy18 (Sep 29, 2020)

ok so do i need to worry about that opening then? or cover it with some 4200? or its fine the way it is?


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## mwolaver (Feb 6, 2014)

lappy18 said:


> ok so do i need to worry about that opening then? or cover it with some 4200? or its fine the way it is?


It seems that most folks just use them as is. My install will cause the TM to ride "backwards" so I sealed my vent holes with silicon RTV (easy to remove). Hope that helps.


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## topnative2 (Feb 22, 2009)

vent holes are there for a reason


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## mwolaver (Feb 6, 2014)

topnative2 said:


> vent holes are there for a reason


I did a whole Ishikawa diagram on having them intact....plugged 'em. I'm planning to use the TM so few times that I never find out if I'm wrong...


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## Fire2126 (Dec 22, 2021)

I think I know what you are talking about. I think you are trying to find out if sealing of the inside of the shaft will be okay. I'm no expert but I think it would be fine. Many kayakers and others rig their trolling motors to operate on PWMs. Most of the time the trolling motor heads are removed and pvc elbows are placed on the end of the shaft to turn the wires down. I'm pretty sure they silicone and/or cap the pvc to prevent water intrusion since not doing so would create an easy way for water to get into the shaft and down to the actual motor. The only issue I have heard is the PWMs crapping out but not the actual motor. I've got a TM on the way and I'm going to seal up the shaft. In a kayak in the ocean, the top of the shaft is to close to the water for my liking so I'm going to seal it.


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## jasonrl23 (Jul 27, 2009)

mwolaver said:


> Just bought a small TM for my boat. The shaft is open at the top. Having recently rebuilt a TM for my dad due to water intrusion in the motor, I question this design feature. The "head" of the TM also has vents; seems to be an easy trip for water into the controls area and down the shaft.
> 
> So, I'm considering a temporary seal like silicon. I'm wondering if the motor heating and cooling is the reason for the shafting being open. What trouble I may be causing myself by sealing the shaft...
> 
> ...


There should be a seal between the upper and lower portion of the control head. At least there was on the few I repaired.


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## redzone1 (Dec 22, 2021)

I would say 4200 or something similar that will not take a nuclear bomb to remove like 5200


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