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 Marshmonster 35HP Longtail Help 
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Joined: Sun Oct 22, 2017 10:38 am
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Post Marshmonster 35HP Longtail Help
Ladies and Gentleman,

BLUF: I am looking for advice on where to find replacement/rebuild parts for the tail shaft of a Marshmonster Longtail.

Background: I am new to working on Mudmotors and specifically the tail shaft itself. A few months ago scouting for ducks I ran into a problem where the actual driveshaft kept moving up through the U Joint hitting the middle of the U-Joint causing a lot of noise. Once I tore it down I found a broke bolt on one of the upper bearings, so long story short I am trying to get replacement parts.....

I have called Marshmonster multiple times, left voicemails, and sent detailed emails asking for help..... now more than 3 months later I am still not getting responses, oh and the do not have a functioning website.

So does anyone have any knowledge specifically on the Marshmonster series Longtail that can help point me in the right direction to find replacement parts from another company that are compatible?

Thanks for any and all help!


Fri Mar 30, 2018 10:50 am
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Joined: Sat Dec 11, 2010 6:25 am
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Location: SWGA
Post Re: Marshmonster 35HP Longtail Help
Call backwater. If they can't help you fix it you should just buy a new kit from them.


Mon Apr 02, 2018 4:18 am
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Post Re: Marshmonster 35HP Longtail Help


Mon Apr 02, 2018 4:43 am
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Post Re: Marshmonster 35HP Longtail Help
Alright guys so, I have replaced the seals and bearings in the upper and lower unit and the set screws on the U joint. Took it out for a spin and the original problem of the driveshaft moving up and hitting the u joint happened again almost immediately.....

So my question is can I weld the driveshaft to something in order to prevent it from moving and if so where?

I have read some threads where it is talked about but I have no idea on what they are welding without pictures....

Here are some picks of the boat and U joint.

Thanks for the help!

Rick


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Tue May 15, 2018 2:51 pm
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Joined: Fri Feb 24, 2012 11:00 am
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Post Re: Marshmonster 35HP Longtail Help
According to the picture it looks like your set screw is on the same side as the shaft key. It seems to me that the set screws should be on the opposite side of the shaft from the key pushing down on the shaft and further driving the key into the shaft. I am no expert but I believe that is how I have my Backwater setup. I could be way off, just a thought.


Thu May 24, 2018 5:42 am
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Post Re: Marshmonster 35HP Longtail Help
Agreed, I would add another set screw on the opposite side. When drilling the other side of the ujoint to be tapped I would drill just deep enough to put a dimple into the shaft for the new set screw to lock into. First I've heard of the marshmonster, but cool.


Thu May 24, 2018 7:11 am
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Post Re: Marshmonster 35HP Longtail Help
I would think you could just loosen the set screw and spin the shaft in the u-joint till the key was opposite the set screw, at least that is how I remember the backwater.


Thu May 24, 2018 2:57 pm
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Post Re: Marshmonster 35HP Longtail Help
How is the set screw supposed to prevent the shaft moving when u don't have a recessed hole for it on the shaft if it is over the key?
On my GD when I replaced the DS, I had to rill a countersink hole for the set screw


Tue Jul 10, 2018 4:16 pm
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Joined: Mon Sep 19, 2011 6:32 pm
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Location: south Florida
Post Re: Marshmonster 35HP Longtail Help
Put in an oversize key?

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Thu Jul 12, 2018 7:13 am
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Post Re: Marshmonster 35HP Longtail Help
https://www.mcmaster.com/#safety-wire-bolts/=1e63abp

Use safety wire bolts and drill/tap a second bolt location 90 degrees from the current location. I'm not a proponent of recessing a shaft where the bolts hit because I've seen them twist in half at that location.
Make sure that you have jam nuts on your prop end the shaft should not be working up that much, if it does it will lock up on the prop end and won't move. If you get it to lock down, you can always shorten the shaft as long as you have enough room on the u joint end for the key to get into the shaft.
Good luck


Wed Aug 15, 2018 11:30 am
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