Need torque for prop nut

GoldToyBox

Cadet
Joined
Mar 6, 2015
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6
Yamaha 115hp 4stroke 2017
Got the repaired prop back from PropMD, lubed everything up and assembled but not sure how much to tighten the nut ..... anyone know the right torque?
 

Texasmark

Supreme Mariner
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Dec 20, 2005
Messages
14,557
Do you think that 55 ft-lbs would be good number for most props on 85HP and up engines? Can't find a torque spec for mine, anywhere.
Yes. I had the 1971 85 triple I bought new and I don't remember the exact number but the shafts are probably the same diameter so the nut should tolerate the same ft-lbs. You don't want it loose.
 

topgun3690

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May 7, 2019
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973
Yes. I had the 1971 85 triple I bought new and I don't remember the exact number but the shafts are probably the same diameter so the nut should tolerate the same ft-lbs. You don't want it loose.
Thanks, Tex.....will try that 55 ft-lb torque spec and see how it goes. (y)
 

topgun3690

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May 7, 2019
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973
Yamaha 115hp 4stroke 2017
Got the repaired prop back from PropMD, lubed everything up and assembled but not sure how much to tighten the nut ..... anyone know the right torque?
Were you satisfied with the service from PropMD? Was thinking about buying a new prop from them.....thanks.
 

Texasmark

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Dec 20, 2005
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14,557
Prop nut just good and snug for the ones that use a cotter pin.
I can't argue with that. Last cotter pin outboard I had/used, I bought new in 1959...an 18 HP Evinrude Fastwin. Had a straight shaft with a hole in it for the "shear (not drive) pin". 3 blade aluminum prop had a rubber slip hub with a metal indent to fit over the pin. After installing the prop, just push it on, install the non threaded prop nut, just a gadget to look pretty, stick the pin through the holes, bend a tab and be on your way. Did it rattle....yes.
 

Faztbullet

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Mar 2, 2008
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All depends on if stock prop or using plastic hub..can range from 55ftlbs to 100ftlbs
 

racerone

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Dec 28, 2013
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Texas----Are you 100% sure that the 59 model 18 HP did not have a threaded prop nut.----Or do not remember ?
 

Grub54891

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Jun 17, 2012
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Texas----Are you 100% sure that the 59 model 18 HP did not have a threaded prop nut.----Or do not remember ?
My 28 hp Evinrude I think from the 70's
has a shear pin. But the plastic nut is held with a cotter pin.
 

racerone

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Dec 28, 2013
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36,269
Agreed the 28 / 33 / 40 HP had a DRIVE PIN and a cap that just slid on with a cotter pin to hold it..----BUT, most of the 18 HP motors had a threaded cap.
 

Texasmark

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Dec 20, 2005
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14,557
Texas----Are you 100% sure that the 59 model 18 HP did not have a threaded prop nut.----Or do not remember ?
Well you have me wondering now. The only threaded nuts I had back then was on my 25 hp Wizard....a Western Auto engine line made by Mercury. It was a spin off from the Mark 30. It had the spin on nut and a dozen or so tabs you bent over to lock the nut to the prop shaft.

All the OMCs of the time were shear and cotter pins......and the bullet nosed gear housing that stuck out and got hung up on everything, and the complicated gasket design used to seal up the LU gear box....more reasons to go with Mercury!
 

Texasmark

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Dec 20, 2005
Messages
14,557
All depends on if stock prop or using plastic hub..can range from 55ftlbs to 100ftlbs
I suppose plastic hubs that require high torque have mounting instructions shipped with the props. 2:1 difference surely would dictate alerting the purchaser I'd think, especially if the person, like me, was used to the 55 spec..
 
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