Prop shaft nut

[2001Sunsport]

Hey guys, replacing the prop on my 2001 Sunsport DD with a ACME 541. Looking to replace the nut and key while I'm in there and was wondering if anyone knew the specs of the nut. I see skidim has them, but I'm assuming I can get a better price from a local place or something like McMaster Carr.

Thanks!

[DKJBama92Mariah]

The thread is 3/4"-10. You may be able to source one locally, but just make sure it's brass. I wouldn't put a carbon-steel nut on a stainless shaft for fear of it seizing on there. These boats came with brass prop-nuts for a reason. My local prop shop usually keeps a couple on hand.

[2001Sunsport]

Thanks!! Looked them up on Mcmaster. A brass nylock nut is ~$10.02, any reason not to use a stainless nylock nut? If I remember right, 316 is marine grade. A type 316 nut is $2.89.

[DKJBama92Mariah]

I believe if manufacturers thought they could get away with using a cheaper nut they would. They could be worried about galvanic corrosion seizing the nut on the shaft, or perhaps they're worried a stainless nut could cause galling when used on a stainless shaft, I cannot say for sure. What I can say is that every inboard boat I have ever seen has had a brass or bronze prop nut. Why risk a $350 driveshaft trying to save seven dollars on a nut?

[2001Sunsport]

Good call, didn't think about galling and ruining the shaft. Thanks again!