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 Prop backing nut stripped 
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Post Prop backing nut stripped
I have a MB kohler 27 LT. I bought a new prop and began to remove the old prop. After using break free, heating and using 3' cheaters, it has barely moved if any. However, it seemed to have finally broken free, but the prop is not moving. The prop and shaft are rotating together, and it seems the backing nut has stripped, and now I'm just spinning my wheels. Prop is trash so no need to save. Not sure if shaft is bent or not, but prop is definitely causing wobble.

What options do I have?

Can I remove shaft with prop on? If so possibly a machine shop to cut off backing nut and prop?

Is a replacement shaft needed? If so, what parts do i need to order to replace.

No service shop anywhere close.



Mon Oct 22, 2012 9:53 am
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Post Re: Prop backing nut stripped
That suck's. It looks like there is enough shaft to use two nuts jammed together that you can use hold the shaft and get the prop spinning. Put a wrecnch on the nuts and hit the prop with a heavy dead blow hammer. Once it is loose you can remove the nuts hold the shaft with a rod shoved through the u joint or a vise grip. I would only do that after I had the prop moving or you may wreck the u- joint or bend a shaft. You might be able to remove the nut with a chisel if it won'spin off. I've done it on lug nuts before. Just make sure the bottom of the nut is supported well when you pound on it so the seals and bearings are not wrecked. Good Luck


Mon Oct 22, 2012 3:34 pm
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Post Re: Prop backing nut stripped
The same thing happened to me on my go devil long tail. I tried everything, I brought it to a local boat shop so they can try and they told me that they gave up cause they was about to break the shaft. I brought it to go devil manufacturer and when they took the shaft out and put it in a vice they finally got it off with the prop removal tool with a stout person on each end. When the prop came off it took all the threads off the shaft with it. There was no saving the shaft, in my case anyways.

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Mon Oct 22, 2012 3:45 pm
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Post Re: Prop backing nut stripped
PITA! I have to believe you best invest in a new shaft. I remove mine a couple times a season, clean the threads, apply anti-seize, and it can still bind up. That's why that hex hub prop offered on bblades.com looks so inviting, and MB's SLT is supposed to come with it standard so prop removal isn't such a chore anymore. Do you run brackish or salt water? Best of luck, let us know what happens.

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Mon Oct 22, 2012 5:54 pm
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Post Re: Prop backing nut stripped
I run exclusively salt water. It's death to the prop and obviously it has everything locked up. Small price to pay I guess. Still cheaper than an airboat.

Well I tried to remove the shaft tonight by removing one of the two set screws with a hammer and socket. The other one is locked up and I don't have an impact. Key seems to be locked up still although it seems the other set is just for pressure. Ill hope I can free it up, but on top of that, some jack wagon at MB decided the shaft needed a half inch tack weld to the u-joint.

So I'm not opposed to cutting the whole thing out, but not really sure where to cut to make sure I don't ruin anything else, and make sure I'm capable of sliding the shaft out. ???... Also, what parts do I need to order? Do I go through MB again or is another brand easier, cheaper, better?

Help?!?!?


Mon Oct 22, 2012 8:17 pm
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Post Re: Prop backing nut stripped
U B F'D

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Mon Oct 22, 2012 8:21 pm
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Post Re: Prop backing nut stripped
Cut the tack weld with a cut off wheel or a chisel.


Mon Oct 22, 2012 8:31 pm
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Post Re: Prop backing nut stripped
as a last try , heat the prop up and put brake fluid on the threads and let sit do it 2 or the times , watch the fumes , the heat opens up the thread face and the fluid will go in
mac

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Mon Oct 22, 2012 8:33 pm
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Post Re: Prop backing nut stripped
New drive shaft $138 shipped to your door from mud buddy. Order all seals while your at it--they are cheap. After you install new shaft and prop take prop off and put it back on every 20 hours to keep the prop from becoming stuck to the shaft--use anti seize.


Mon Oct 22, 2012 8:36 pm
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Post Re: Prop backing nut stripped
sounds like a good time to replace the shaft,prop and seals and make every thing new ,that way you know things are are done right.


Mon Oct 22, 2012 9:02 pm
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Post Re: Prop backing nut stripped
Thanks for the replies. I will order the new parts tomorrow, hopefully have them ready to go by the opener in 12 days.

So how the heck do I get this current shaft off/out?

Cut off below the U-joint, pound on prop to slide shaft out, then knock the rest of shaft out of u joint?

Better ideas?


Mon Oct 22, 2012 9:38 pm
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Post Re: Prop backing nut stripped
I know a nut cracker on the nut would take care of it but not sure if it would work on prop. I have used one alot on restoring muscle cars from the 60's. Good luck man


Tue Oct 23, 2012 11:10 am
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Post Re: Prop backing nut stripped
KD tools sells the best one to use


Tue Oct 23, 2012 11:11 am
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Post Re: Prop backing nut stripped
zip wheel in an air grinder/cutoff tool. slice into the prop till you are almost to the threads, put something solid opposite of your cut and put a cold chisel in the cut, proceed to beat the chisel to death or until the prop loosens its hold on the threads, if neccessary repeat on the opposite side of the prop, If this doesnt do it then just cut the shaft off and replace the whole works.


Tue Oct 23, 2012 12:33 pm
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