# Proper torque on prop nuts



## Play'N Hooky Too (Sep 29, 2007)

I am installing the props onmy project boat and was trying to determine the proper torque for the prop nuts.The boat has twin inboards with 1-1/4" stainless steel shafts (7/8" prop nuts).The manual says to consult the manufacturer for proper torque specs but I have not been able to get any info from Silverton. I referred to a standard torque spec table that Ilocated in some engineering reference materials thatI have and it says for 316 stainless 7/8" bolts with 14 threads/inch that the dry torque should be about 200 ft-lbs. I've put a light coating of anti-seize on the shafts so I was going to reduce that by 25% (~150 ft-lbs) as recommeded for "wet" torque specs. Am I in the ballpark on this?

Thanks

Alan


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## Tuna Man (Oct 2, 2007)

On a MercCruiser Alpha Drive........

Torque to an initial 55#. Then continue until the lock tab can be bent in place.


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## Sequoiha (Sep 28, 2007)

Ron is correct on alphas,,, i torque outboards to 40 ftlbs....


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## Play'N Hooky Too (Sep 29, 2007)

Thanks for the responses gentlemen. I know onmy outboard the torquerequirement isn't that high becausethe prop is resting on the thrust washer and the shaft is splined. But in this case, the shafts are smooth tapered with a key, so I figured the torque requirement would be higher. I snugged them on pretty good last night and the props were still moving up the shafts a little with each turn of the nut. I didn't want to over do it so I stopped until I could consult with theexperts.

Thanks

Alan


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## The Maintenance Shoppe (Nov 5, 2007)

inboards, transmissions, 1.25" prop shaft. torque prop nut to 125-150 ft lbs. Do not use anti seize in threads, use marine grease.


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## Play'N Hooky Too (Sep 29, 2007)

> *TMS (1/20/2010)*inboards, transmissions, 1.25" prop shaft. torque prop nut to 125-150 ft lbs. *Do not use anti seize in threads, use marine grease*.


Thanks for the response. Well, as it turns out, when I said "anti-seize" I meant "OMC Trailer Bearing Grease" because that is what I actually used on both the prop shafts and the prop nuts. I just wasn't sure that was appropriate.

Thanks for all ya'lls responses.

Alan


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