Torque spec for prop nut

[fire831]

I have a 1978 85 H.P. Evinrude, and can't find the torque spec in my manual for the prop nut. Thanks for any help. Also if anyone knows where it's located in the original manual, please tell me. What is the easiest and safest way to hold the prop from turning while torquing the nut without damaging anything?

 

[Skid-joe]

Re: Torque spec for prop nut

Put a piece of 2x4 up under the ventilation plate.
As for the torque, my mercruiser i/o state 55 Ft-Pd but you will find many just torque up snug and a bit.

god luck...........................joe

 

[Texasmark]

Re: Torque spec for prop nut

My 90 hp Merc serv man Printed in late '90's, says 55 ft-lbs also, but that's for the rubber hub. Sounds like as good a guess as you are going to get.

On new props with the plastic removable hub, I have seen it batted around several times herein, that the mfgr's recommended torque for that hub is 100 ft-lbs.

HTH

Mark

 

[fire831]

Re: Torque spec for prop nut

Thanks for the help.

 

[WaterWitch2]

Re: Torque spec for prop nut

My factory service manual for my 1978 140hp says "Install and tighten propeller nut finger tight and then tighten to align next cotter pin hole. The propeller shaft should turn freely (engine in NEUTRAL) after propeller is installed. Install cotter pin (use new pin if necessary) bending ends over nut." This info is at the very end of the "lower unit" chapter.

 

[fire831]

Re: Torque spec for prop nut

Thanks WaterWitch2.

 

[Texasmark]

Re: Torque spec for prop nut

More confusion..................

So we have 2 different systems here; one uses a self locking nut (nylon insert) and a SS tab plate that locks into the prop to keep the nut from coming off.....Merc.

Apparently OMC has a nut also,but it has ears on it and a hole in the propshaft to accept a cotter pin to keep it from coming off.

Now, the difference between the hubs on the props of both engines is the number of splines. Merc uses 15, don't know what OMC uses; doesn't matter.

So from the (proper operation of the) prop standpoint, what difference does the nut torque make to the rubber hub performing properly? Apparently none.

Well the Merc prop nut, with all it's applied torque, isn't going to come off if it were finger tight either, cause it has 2 locking mechanisms to prevent it.

So this translates to me that it doesn't matter what the !@#$%^&*()_+ torque on the nut is!

Then in comes the new plastic hubs at 100 ft-lbs. Guess you are going to have to ECN both mfgr's manuals.

My 2c,

Mark

 

[fire831]

Re: Torque spec for prop nut

I think I'll just put it back on and tighten it enough to make sure there's no play in it and leave it at that. Thanks for the help. If I would happen to find a definite torque for it, I will post it.